Piezoelectric actuators are widely used in precision mechatronic systems, but their capacitive load and high-voltage requirements make efficient, low-distortion driving electronics challenging. This thesis presents the structural design and implementation of a mixed-signal Class-H amplifier intended for piezo applications. This amplifier makes use of an isolated Class-AB amplifier and an isolated Class-D amplifier to achieve low power losses and high charge accuracy. A system-level architecture is developed from actuator requirements and translated into key circuit blocks, including the supply modulation strategy,sensing and feedback paths, and the digital control and isolation interfaces. For this digital control of the amplifier a novel digital circuit calculator and simulator have been build. Experimental results on a prototype hardware platform demonstrate regulated rail tracking, improved efficiency compared to Class-AB operation, and output performance suitable for driving piezoelectric loads. The developments in this prototype allow for further development into Class-H and digital feedback amplifiers. ... Read more

The Lunar Zebro team creates a rover that will be deployed on the lunar surface. The rover consists of multiple subsystems, each with its own power requirements. To ensure reliable operation, the rover is equipped with another subsystem, the Electrical Power System (EPS). This system distributes electrical power throughout the rover, continuously monitors the remaining energy stored in the battery pack, and manages the charging and discharging processes. The EPS also consists of a Battery management system (BMS) which monitors the batteries and keep them within a save voltage and current range. This thesis presents the design, implementation, and validation of a battery management system and battery pack for integration into the Lunar Zebro EPS. A conceptual EPS design with BMS and battery pack is created using energy budget estimation and power modeling. A simulation tool is developed to evaluate the charging and discharging behaviour during walking and charging scenarios of the rover throughout the mission. Based on these simulations, a suitable battery type is selected with focus on temperature tolerance, charging behaviour and reliable operation.
The Battery Management System developed in this work is designed and tested for its protective features, including overvoltage (OV) protection, undervoltage (UV) protection, overcurrent discharge (OCD) protection, and short-circuit discharge (SCD) protection. The BMS operates using I2C communication with an additional CRC bit to protect against bit errors. This work builds on earlier iterations of the existing EPS.
The BMS is built as a modular unit that can be integrated into the EPS. The bidirectional converter is also taken and redesigned as a separate module to improve accessibility and simplify debugging. This modular design improves development and testing at the cost of reduced compactness. Finally, the battery pack, the individual cells, and the BMS are tested to gain a clear understanding of the system behaviour in the rover. The results show that the BMS and the battery pack behave well and operate as intended. The integration of the bidirectional converter is shown to work conceptually. Some issues remain in the current physical board, which could not be resolved within the scope of this thesis and are left for future work.
https://zebro.tudelft.nl/ ... Read more

This thesis explores the design and development of a bio-inspired robotic module that enhances intuitive human interaction within a swarm robotics context. The work addresses a research gap in Human-Swarm Interaction by focusing on how individual swarm robots can express emotions and respond to humans in meaningful, non-verbal ways, drawing inspiration from both domesticated animals, like dogs, and arthropods. The project integrates sensory and expressive components such as eyes, antennae, and body movement into a modular "symbiote" that can be mounted on existing robots. Through iterative prototyping, user studies, and expert consultations, the research identifies key emotional states and corresponding expressive behaviors, culminating in a module that communicates through movement of its appendages. The module supports real-time interaction and demonstrates the potential for robots to form more natural and intuitive relationships with human users, especially in exhibition environments like TU Delft’s Cyber Zoo. The findings contribute to the fields of bio-inspired design, swarm robotics, and human-robot interaction by offering a novel approach to enhancing emotional legibility and engagement in robotic swarms. ... Read more

This report details the design and implementation of a custom battery management system, tailored to the needs of the Delft Hyperloop dream team. The goal of the custom battery management system is development time reduction for future Delft Hyperloop teams, modularity which allows prototyping with various battery sizes and compliance with the rules and regulations of the hyperloop competition. The core functionalities of the battery management system include safety cell monitoring, cell group balancing and communication. Cell group balancing entails the determination of the amount of charge present in a cell group and consequently, taking action which leads to all cell groups having an equal amount of charge, this ensures performance, longevity and safety of the battery pack.

The battery management system discussed in this report, consists of a prototype printed circuit board which can manage up to 18 battery cell groups. The prototype is centred around a battery stack monitor integrated circuit, which allows high voltage measurement, balancing control and isolated communication. The integrated circuit supports 18 cell inputs with as many cell balancing outputs. The cell balancing outputs drive PMOS transistors which allow excess energy in cell groups to be dissipated in special resistors. Furthermore, a multiplexer is present on the prototype, which allows sixteen cell temperature measurement inputs to the battery stack monitor integrated circuit. Finally, a shunt resistor is present on the prototype, allowing for an accurate current measurement. The prototype has been developed with modularity in mind, the circuit allows to be chained up with multiple circuits of the same type, allowing the management of potentially up to hundreds of battery cell groups. ... Read more

With the rising demand for high-bandwidth, high-resolution current sensors, commonly used Hall-effect devices fall short due to their relatively high wide-band noise. The coil-Hall hybrid architecture addresses this issue by combining the Hall plate with a pick-up coil, known for its high SNR at high frequencies. This CMOS-compatible architecture achieves excellent noise and bandwidth performance while maintaining the ability to sense DC signals. However, this performance comes at the cost of increased complexity in combining, calibrating, and stabilizing the two distinct signal paths. This thesis thoroughly investigates the various challenges and trade-offs associated with this architecture and provides a comprehensive overview of potential system solutions. Additionally, the insights gained were used to design a prototype chip for SystematIC Design B.V. Seeking to reduce complexity, this led to the invention of a new system architecture. This new architecture effectively overcomes several challenging trade-offs that have hindered existing designs until now and is considered a promising approach for achieving even better performance in the future. ... Read more

The Lunar Zebro rover is a nano rover designed by student research team Lunar Zebro at the Technical University of Delft. This rover will be sent to the lunar surface to conduct scientific experiments. In order to protect the rover during transit and facilitate successful deployment onto the lunar surface, a rover deployment system was designed.

This thesis describes the design of the sensing and actuation part of the rover deployment control system. The thesis details the design of a system which is able to deploy 4 Non-Explosive Actuators by means of sequentially supplying more than 4A for 50ms to each NEA. This sequence is inhibited by a physical connection to the rover by means of an umbilical cord which can be overridden when the rover and microcontroller send an override signal at the same time. The system contains a heating element and two temperature dependent relaxation oscillators that can be used to regulate the temperature. Thermal regulation can function independently of a digital control system, but can also be managed by the microcontroller. In the case that the microcontroller experiences failure, the NEA activation sequence can be initiated by two control signals from the lander, to which the deployment system is attached.

The system has not been physically tested, but has been verified in simulation. The combination of all these subsystems uses a peak power of 1.1W in simulation.

A test printed circuit board was designed to incorporate the complete rover deployment control system. This board can be used to physically simulate the deployment of the four non-explosive actuators by means of glass fuses. The board also allows any equivalent NEA model to be used in order to verify the limits of the system.

The system meets all functional requirements in simulation. Future work regarding the design entails physical testing of the PCB and the resolution of two major vulnerabilities, namely its reliability on the stability of the lunar lander’s 28V supply as well as its inability to handle excessive thermal energy. ... Read more

The Rover Deployment Software System (RDSS) is a critical component designed to ensure the successful deployment of the Lunar Zebro rover onto the lunar surface. This thesis presents the design, implementation, and testing of the RDSS, which consists of three primary subsystems: a communication system between the lander and the RDSS, an electronic control system, and an integration with an existing rover communication system. Moreover, the existing rover communication system will not be covered in this thesis due to the implementation being done by the Lunar Zebro team in the future. The RDSS is tasked with managing the deployment sequence, providing power during transit, and facilitating communication between the rover and the lander. Key challenges addressed include handling the harsh lunar environment, ensuring reliable communication, and adhering to strict weight constraints. Extensive testing, including unit, integration, system, and performance tests, validated the system’s robustness and reliability. The insights and methodologies developed are intended to support the Lunar Zebro mission and inform future projects involving space deployment systems. ... Read more

This thesis details the design and development of the Power System for the Rover Deployment System. This power system delivers and manages the necessary power required by the entire Rover Deployment System. The RDS is responsible for ensuring the rover’s survival inside the transportation pod during transit. It also handles releasing the rover, which a mechanical mechanism will lower onto the lunar surface. The goal of Lunar Zebro is to send a nanosatellite to the moon for lunar surface exploration and radiation measurements. The power system was designed to power the MCU and transceivers at 3.3V, to provide power for rover charging at 12V, and to charge a capacitor bank used to provide the necessary actuation power to the NEAs. An electrically triggered umbilical release mechanism, unfortunately, could not be implemented due to a lack of available data. The circuit for this system was created, simulated, and added to the PCB design of the RDS. The simulations of the circuit behaved desirably. Due to the lead time on orders, the PCB has unfortunately not been received yet. Because of this, the entire power system has unfortunately not been tested yet. ... Read more

Class D amplifiers find widespread application in audio devices for driving load speakers, primarily due to their remarkable efficiency. Nonetheless, this enhanced efficiency often comes at the expense of reduced linearity. Hence, techniques for reducing Total Harmonic Distortion (THD) are important in the context of class D amplifiers.

The analysis of the distortion mechanisms is first presented. Specifically, emphasis is placed on the distortion generated within the power stage, encompassing aspects such as deadtime distortion and rising and falling time distortion. Both of them are found to be related to the input signal. Subsequently, the compensation technique is applied to the conventional class D amplifier to reproduce and cancel the error. The idea of the compensation approach involves modifying the amplitude of the triangular waveform based on the input signal. A 12 dB THD improvement is achieved in the concept verification section, which is conducted in LTspice.

The negative feedback serves as another technique to achieve THD reduction. A straightforward two-step design methodology is presented to avoid design iterations in the concept design phase. The phantom zero technique is applied when doing the frequency compensation of the feedback loop. The validation of the concept is performed through the use of SLICAP, while the circuit implementation and simulations are carried out within Cadence. Remarkably, this technique results in an impressive -111.8 dB THD reduction, achieved when the output power equals 1 W. ... Read more

This report presents a bandgap reference voltage source that achieves 5-sigma Inaccuracy of ±0.5% from -40C to 150C under 16FFC process. This is the first time 16nm techniques are used in automotive products and the first time trying to realize analog circuits in such a process for in-vehicle network purposes. The report points to good behavior with only a small area and considerable power. It also proves that applying chopping to the circuit does not increase the area. ... Read more

Lunar dust presents a serious problem for future lunar rovers. Due to the charged nature of this fine dust, it tends to stick to sensitive elements like solar panels. It is clear that a system needs to be implemented in order to remove lunar dust to keep the output power of the solar panel at a satisfactory level. This paper develops the proof of concept electronics for a method sometimes called an electrodynamic screen, that uses electrostatic fields to sweep away the dust adhered to the surface of the solar panel. The electronics for this system needs to produce a high voltage three phase pulse wave in order to drive the electrodes placed on top of the solar panel. The design of the electrodes themselves are not part of this thesis, but it is the main subject of the companion thesis produced by other members of our group. ... Read more

This project focuses on building a wireless charging station for the Lunar Zebro robots and building upon the existing functionalities by matching the interfacing voltage and current requirements for the wireless power transceiver. ... Read more

The goal of this thesis is to develop a ROS package that facilitates the control and navigation of a Duckiebot robot. With the rise of robot swarms the need for autonomous charging system for robots is increasing. An implementation for decentralised autonomous behaviour for a Duckiebot for a wireless charging system in a Duckietown environment is discussed. The devised system is divided among three different modules and is implemented in ROS:
• An image recognition module;
• A navigation module;
• A motion control module;
The image recognition module uses linear image processing techniques and YOLO object detection in order to detect objects in images from the robots front facing camera. It detects traffic lights and road markings in order to tell the robot where to go.

The navigation module uses odometry to keep track of the robots current position. The odometry is reset in order to maintain accuracy. When the battery of the robot reaches a certain point the robot will decide to
charge. It will then initiate path finding using Lee’s algorithm in order to find a path to a charging park.

Finally the motion control processes all the information in order to drive the wheels of the robot.
The system is thought to be able to navigate to a charging station, charge and then leave the charging station using the designed ROS package. ... Read more

This thesis aims to solve the problem of designing the hardware for a wireless charging system to be used for keeping an autonomous robot swarm alive. Previous designs available to us lacked essential safety features and were very specific in their application. Current wireless charging specifications are also not sufficient to cater to the needs of these systems. Using a detailed analysis and clear requirements, this thesis describes the process of developing the hardware for such a system with flexibility and safety in mind. ... Read more

One of the major challenges faced by future robotic and human missions to Mars and the Moon is the presence of atmospheric dust. The Lunar Zebro rover which is intended to walk on the Moon is powered by solar panel. Due to its surrounding terrain, which mostly consists of small particles, the rover may be a potential target for dust accumulation, which reduces its output power. For the longevity of any space mission, it is important to have a long-lasting source of energy. That is why during this project, an Electrodynamic screen is constructed which could remove dust from a 100 x 100 mm area without containing moving parts. One subgroup concentrated on building the electronics necessary to create a high voltage (~1.6kV) three-phase drive signal, the other group focused on the electrodes of the system and described the effects of an electric field on dielectric particles. These are mostly found on the Moon. Different electrode architectures are proposed, but the zigzag architecture was found to be the best suited for a possible dust removal system. Furthermore, the higher voltage applied to the electrodes, the greater the forces exerted on the particles are. Further research should be conducted for any possible implementation. It is recommended to also read the other thesis. ... Read more

The unique six-legged swarming rover Lunar Zebro is designed and produced by students from the Delft University of Technology. The objective of the rover is to accomplish an autonomous mission on the Lunar surface by 2024. This thesis evaluates a path planning algorithm that is designed for autonomous navigation in the Lunar environment. The thesis studies existing path planning algorithms and determines the essential functionalities of the algorithm and the unique requirements of Lunar Zebro. It is found that an Artificial Potential Field based path planning algorithm accommodates the determined needs and requirements.
With the help of the Artificial Potential Field path planning algorithm and the unique requirements, a vector field based algorithm is developed. The algorithm uses an attractive vector field to attract the rover to the determined target. Meanwhile, obstacles or other obstructions are denoted by a repulsive rotational vector field around the edge of the obstacles. This rotational repulsive force ensures obstacle avoidance and prevention of the local minimum trap, which often occurs in Artificial Potential Field path planning. Improvements are suggested to increase reachability and decrease path length and planning time of the rotational vector field algorithm. In the Python developed simulation, the improved algorithm accomplishes a 62% reduction in planning time compared with the original Artificial Potential Field algorithm and achieves similar path length results. Moreover, the proposed algorithm has a reachability of 90% where the Artificial Potential Field algorithm just reaches a success rate of 55%.
The thesis concludes with the future work recommendations for a low level implementation in C or either C++ to facilitate the deployment in a microcontroller. ... Read more

Labour in the agricultural sector is in short supply, while a large portion of the work is still being done manually. To speed up the work and guarantee the food supply of the future, Lely has started a project on agricultural automation. The aim of the project is to create a robot that can perform multiple repetitive tasks simultaneously, to allow for a large portion of the weekly work to be automated.

As a first step in the automation process, the decision was made to create a specialised robot arm. The hardware and software design of this robot arm will be discussed in this thesis. Arm control including inverse kinematics was built from scratch to optimise for a SCARA type robot arm while keeping the required processing power low.

To evaluate the arm design, lab tests were conducted on a specific task. During the lab test, the task was performed by the designed robot arm.
An average of 20 consecutive successful runs has been achieved. Although these results are promising, there is room for improvement in both the object detection, as well as the smooth control of the robot arm.
... Read more

In this report the analysis of underwater communication using electric quasi-static fields is undertaken, in which key aspects that influence the performance the communication between a transmitting and receiving electrode is examined. A mathematical model was proposed for the transmission and reception of the quasistatic field and the expected amount of atmospheric noise at the receiving electrode. The quasi-static model of the electric field is verified using a measurement setup, which entailed the measuring of transmission and reception between electrodes and the impedances and noise of different types of electrodes. In small box of water (30L) it was shown that the quasi-static model matches the measurements and the size of electrodes influences the transmission and reception. In general, decreasing the resistance of the transmitting electrodes allows for the charge to be easily transferred from the electrode to the water increasing the amount of transferred power into the water and by reducing the impedance of the receiver reduces the noise measured at the input. ... Read more

Unmanned underwater vehicles benefit from communication with a high data rate on relatively small distances (under 100 m). Existing communication methods are not able to provide this or present other shortcomings. Therefore, this bachelor end project focuses on a new type of underwater communication, quasi-static electric field communication. The software and modulation techniques in such a communication system are covered in this thesis. This includes a detailed analysis of modulation techniques, and especially of differential methods such as pi/M-DPSK, which can be demodulated non-coherently. Our system implements OFDM and according to simulations, it is able to achieve data rates of up to 1 Mbit/s. Additionally, this research focuses on the effect of error correction coding on the performance of the system. Moreover, an adaptive data rate control system is designed. The efficiency of the system is optimized by a power distribution algorithm. Finally, suggestions are given for a communication protocol. ... Read more

As electromagnetic waves cannot propagate sufficiently far in water, underwater communication is mainly performed using either acoustics or optics. However, none of these technologies have been proven to be completely effective in every situation. Therefore, research in new underwater communication systems can still bring large benefits to a wide range of different underwater technologies.
During this project, a promising new type of underwater communication system based on electric fields has been investigated. While two subgroups have been working on the characterization of the communication channel and different modulation techniques, this thesis focuses on the hardware needed for optimal communication. Moreover, this hardware includes both a low-noise receiver and a high power transmitter. An analysis of different design options, the detailed design of one of these options and the validation of the design are given in this report. However, to get a complete overview of the designed communication system and its performance, it is recommended to also read the other two thesis reports.
... Read more