Development of a Design Methodology for Cloud Distributed Control Systems of Mobile Robots

This article addresses the problem of cloud distributed control systems development for mobile robots. The authors emphasize the lack of a design methodology to guide the process of the development in accordance with specific technical and economic requirements for the robot. On the analysis of various robots architectures, the set of the nine most significant parameters are identified to direct the development stage by stage. Based on those parameters, the design methodology is proposed to build a scalable three-level cloud distributed control system for a robot. The application of the methodology is demonstrated on the example of AnyWalker open source robotics platform. The developed methodology is also applied to two other walking robots illustrated in the article.

HEXAPOD MOVEMENT ALGORITHMS TO AVOID INTERFERENCE. ANGULAR MOVEMENT

This paper considers the possibility of using a stepping robot - hexapod for research, monitoring the condition of technical dry channels, enclosed spaces and more. Compared to existing designs used today, the hexapod has a list of advantages that make it a more versatile tool, namely: autonomy, due to the power supply installed at work, design features that ensure its increased patency on uneven surfaces. Instead, this type of work requires the development of complex algorithms for movement than in the case of wheeled or tracked machines, ie. hexapod is a platform that moves the limbs, which in turn move with the help of servos. Therefore, the movement of the platform is provided by the control of each servo. In addition, environmental information is additionally processed from rangefinders, limb con-tact sensors with the surface, cameras, accelerometers, etc. Particular attention is paid to robot rotation algorithms, as the proposed scope imposes restrictions on the ability to maneuver freely in space. An algorithm for rotating robots in confined spaces based on limb state matrices has been developed, which greatly simplifies the practical implementation and allows to easily change the type of stroke during the hexapod operation. It is also proposed to introduce a buffer state matrix, which allows you to remember the last position of the limbs of the robot in case of its failure, after the elimination of which, it is possible to continue moving from any last state. Or return to the starting position and change the route. The versatility of the algorithm allows its use not only in the development of the software part of the hesapod, but also for other types of walking robots. Since the developed algorithm allows you to easily modify the types of moves at each iteration of the step. In the future, it is planned to test this algorithm on a model of a hexapod and supplement it with the necessary components for vertical movement, which is very important for passability in this area of application.

Shrimp Robot Mechanism

The Shrimp rover is highly suitable for planetary exploration missions because of its unconventional wheel order, in-built passive adaptability and good ability to climb obstacles. It is a spatial multi-body system and a multi-variable, multi-parameter coupled non-linear system. Thus, kinematic and dynamic analyses for such systems are complex and time consuming. Long-range robotic missions for Martian exploration imply a high degree of autonomy. The most advanced locomotion concepts are based on wheels or caterpillars (e.g. Sojourner, NASA or Nanokhod, ESA). These rovers have clear advantages regarding power efficiency and complexity if compared with walking robots. However, they still have quite limited climbing abilities. Typically they can only overcome obstacle smaller than their wheel size. In this paper we present Shrimp, an innovative long range rover architecture with 6 motorized wheels. Using a rhombus configuration, the rover has a steering wheel in both, the front and the rear, and two wheels arranged on a bogie on each side. The front wheel has a spring suspension to guarantee optimal ground contact of all wheels at any time. The steering of the rover is realized by synchronizing the steering of the front and rear wheel and the speed difference of the bogie wheels. This allows for high precision maneuvers and even turning on the spot with minimum slip. The use of parallel articulations for the front wheel and the bogies enables to set a virtual centre of rotation at the level of the wheel axis while maintaining a high ground clearance. This insures maximum stability and climbing abilities even for relatively low friction coefficients between the wheel and the ground. This rover is able to passively overcome unstructured obstacles of up to two times its wheel diameter. With this high mobility, this architecture is the perfect candidate for long range planetary missions.

Foot trajectory analysis of a robotic leg

When it comes to walking robots, foot trajectory is a crucial element that can significantly influence the efficiency of the walking robot. This paper analyses the various foot return trajectories, which can provide higher step length while consuming less power. It is done through mathematical analysis and verified using simulations in software such as MSC Adams and Solidworks. This paper also discusses the kinematic and dynamic analysis of the two degrees of freedom leg using theoretical approaches in MATLAB and verifies the results using the simulation in MSC Adams.

Organization of walking of the lower-extremity exoskeleton using the control of the supporting foot

Introduction. The development of robotics in many advanced countries has raised various industries to a high level. The demand for robots increases the share of their use in production tasks, mainly in the motor-vehicle and electronics industries. Advanced robotics can increase productivity in many industries by 30%, while reducing labor costs. Automation of technological processes of electronics production has a positive impact on the use of robots. Robots are used in construction, logistics, oil and gas, aerospace, plant engineering and construction, mining, healthcare, etc. The authors consider robots from the point of view of their application in medicine for the rehabilitation of musculoskeletal patients. This paper describes the mechanisms for controlling the feet and the center of mass of a humanoid robot.Materials and Methods. The authors chose the simplest algorithm for searching for the law of motion control of a humanoid robot. The robot movement was presented as a reverse pendulum. Using the large kinematic redundancy of walking robots, we have developed a way to control the robot in such a way as to bring the dynamics of its movement to the reverse pendulum as close as possible. At the same time, the problem of determining the generalized coordinates is considered, at which a given position and orientation of the transferred foot and a given position of the projection of the center of mass (CM) of the robot onto the reference surface are provided.Results. The authors have developed a digitalized automatic control scheme for the movement of the feet and the center of mass of the human exoskeleton, which will largely reduce the load on a sick person.Discussion and Conclusions. When discussing the results, comparing the data of the tables obtained during the calculation, the following conclusion was made. The scheme for controlling the feet movement of a human exoskeleton developed by the authors is most effective when designing an automatic scheme for controlling the movement of the feet and the center of mass of a human exoskeleton using digital technology, which will largely reduce the load on a sick person.

Variable-time-interval trajectory optimization-based dynamic walking control of bipedal robot

Bipedal robots by their nature show both hybrid and underactuated system features which are not stable and controllable at every point of joint space. They are only controllable on certain fixed equilibrium points and some trajectories that are periodically stable between these points. Therefore, it is crucial to determine the trajectory in the control of walking robots. However, trajectory optimization causes a heavy computational load. Conventional methods to reduce the computational load weaken the optimization accuracy. As a solution, a variable time interval trajectory optimization method is proposed. In this study, optimization accuracy can be increased without additional computational time. Moreover, a five-link planar biped walking robot is designed, produced, and the dynamic walking is controlled with the proposed method. Finally, cost of transport (CoT) values are calculated and compared with other methods in the literature to reveal the contribution of the study. According to comparisons, the proposed method increases the optimization accuracy and decreases the CoT value.