The TU Delft ZEs-Benige RObot (Zebro) project is presented with the opportunity to bring the Zebro concept to the surface of our moon. To maximise the probability of success, the Locomotion Sub-System (LSS) software of Lunar Zebro is developed using a novel model-driven design tool called Dezyne. Dezyne uses a proprietary language to describe systems, perform model checking and execute source code generation. Dezyne is proposed for this thesis as it can improve the quality of the LSS design. This is required because the project is under strict time- and manpower constraints. The goals for this thesis are:
i. Deliver a reliable software design for the Locomotion Sub-System (LSS) of Lunar Zebro.
ii. Deliver a working implementation of the Locomotion Sub-System (LSS) software design on Lunar Zebro’s hardware.
iii. Investigate the advantages and disadvantages of the use of the model-driven software design tool Dezyne.

The current workhorse of the Zebro Project, is a Zebro called DeciZebro. Lunar Zebro builds on the legacy of the design of DeciZebro. The LSS of Lunar Zebro consists of an Locomotion
Controller (LC) and six leg modules. The requirements of the LSS software of Lunar Zebro are derived from the requirements of Lunar Zebro as a whole. These requirements are categorised according an European Space Agency (ESA) standard.

With the help of Dezyne, the system is designed, verified, simulated and integrated into native code. It is found that Dezyne is not suitable for designing the software of the leg modules.
Therefore, the LC consists primarily of generated code, while the leg modules solely contain code developed by hand.

The goals of this thesis are partly reached. An LSS software implementation is delivered with the use of Dezyne. However, the design is lacking a framework in which errors that occur
during operation can be resolved by means of extensive state machining. This is due to time constraints. Additionally, it is unclear if this specific LSS software implementation is more reliable than an implementation that is made without the use of Dezyne. The third goal, listing the advantages and disadvantages of Dezyne, is fulfilled. ... Read more

In this thesis, a swarm is defined as: ”A swarm is a large number of homogenous, unsophisticated agents that interact locally among themselves and their environment, without any central control or management to yield a global behaviour to emerge.” The bigger perspective is to have the units within a swarm operate for a potentially infinite amount of time, thus making algorithms and energy use as effective as possible. The research is split up in different sections: sensors, communication and behaviour. The behaviour is split again: individual behaviour, anti collision behaviour and swarming behaviour. The research on the sensors and communication points out that the Bluetooth Low Energy (BLE) sensor is the most suitable for an autonomous Zebro Swarm. BLE can be used to transfer data as well as serve as a range sensor. As a communication device, BLE offers the ability to advertise data an has a range of 50 meters which is sufficient for application in a swarm. As a sensor, BLE offers fairly accurate measurements in distances below 1 meter. Due to the properties of radio signal strength and the always present radio frequency noise, the accuracy decreased with increasing distances. The individual behaviour aims at exploring as much area as possible, with the amount of energy available. The energy use therefore has to be minimised and the explored area maximised. Since little is known on the energy use, this is assumed constant. Maximising area, however, has some key elements. The first is to keep moving; standing still results in energy use without exploring new terrain. The second is to make only gentle turns; the rotational centre must be outside of the detection distance. When this centre lies inside of the detection distance, the inner turn will cover area for a longer period making the turn ineffective. The anti collision behaviour should prevent units from making physical contact. By using a contactless sensor an approaching collision can be detected. Changing the parameters of the movement of the units at the moment they enclose more than a certain value prevents the collision. The anti separation behaviour should prevent units from separating from eachother. This can be done by making units turn 180 degrees once the relative distance reaches a certain limit. The turning on a certain limit is a simple algorithm and thus requires little processing power. Apart from the anti collision behaviour and the anti separation behaviour, there is another approach to deal with these behaviours. Since the units are able to communicate with each other, they can also advertise their location to other units. There are several methods for a unit to acquire their location. These methods are divided in approximate and exact location estimation methods. The Trial and Error method is placed in the first category, the exact location estimation methods are: Time Based, Internal Reference, External Reference and Radar. The External Reference method is considered the most applicable of these methods since it is relatively accurate, simple and provides a direct location. ... Read more