Robot Control Parameters Research Articles

Online Learning of Uneven Terrain for Humanoid Bipedal Walking

We present a novel method to control a biped humanoid robot to walk on unknown inclined terrains, using an online learning algorithm to estimate in real-time the local terrain from proprioceptive and inertial sensors. Compliant controllers for the ankle joints are used to actively probe the surrounding surface, and the measured sensor data are combined to explicitly learn the global inclination and local disturbances of the terrain. These estimates are then used to adaptively modify the robot locomotion and control parameters. Results from both a physically-realistic computer simulation and experiments on a commercially available small humanoid robot show that our method can rapidly adapt to changing surface conditions to ensure stable walking on uneven surfaces.

Modelling of Bound Estimation Laws and Robust Controllers for Robustness to Parametric Uncertainty for Control of Robot Manipulators

In this paper, first, a new approach is proposed for derivation of bound estimation laws for robust control of robot manipulators. In this approach, functions depending on robot kinematics and control parameters and integration techniques can be used for derivation of the bound estimation laws based on the Lyapunov theory, thus, stability of the uncertain system is guaranteed. Five new bound estimation laws are proposed, and in this derivations, five novel functions depending on robot kinematics and control parameters and proper integration techniques, such as substitution method, integration by part and integration by partial fractions are used. Then, four new robust control inputs are proposed based on each derived bound estimation law. Lyapunov theory based on Corless and Leitmann (IEEE Trans Automat Contr 26:1139---1144, 1981) approach is used for designing the robust control input achieving uniform boundedness error convergence. This study also allows derivation of other bound estimation laws for robust controllers provided that appropriate novel functions and proper integration techniques are chosen.

S1902-1-3 月面でのロボットの動力学解析(宇宙システムの誘導・制御)

This paper describes a dynamics simulation of a humanoid robot on the moon. We are developing a humanoid robot simulator. This simulator is specialized for humanoid robot. Using this simulator, we evaluated walking performance on the moon. Humanoid robot walking controller parameters depend on gravity. As the gravity on the Moon is only one-sixth of that on the Earth, humanoid robot control parameters should be changed. In this paper we simulate a humanoid robot walking on one G and one-sixth G

Emulation of Space Robotics Control by Implementing a Test-Bed System

The main objective of this research work is to build a test-bed for space robot emulation system that operates in the “zero or less gravity” environment. To achieve this, a 2-DOF SCARA robot with a unique instrumental arrangement was contracted which will compensate the gravity force. The robot dynamic model and control parameters were studied through the Newton-Euler formulation. Real time-data was collected from the feedbacks of the encoders and controlled through the PC interface card. This mechanical emulation setup is useful for the space robot control system modeling and validation.

Flexible real-time mobile robotic architecture based on behavioural models

Behaviour-based models have been widely used to represent mobile robotic systems, which operate in uncertain dynamic environments and combine information from several sensory sources. The specification of complex mobile robotic applications is performed in such models by combining deliberative goal-oriented planning with reactive sensor driven operations. Consequently, the design of mobile robotic architectures requires the combination of time-constrained activities with deliberate time-consuming components. Furthermore, the temporal requirements of the reactive activities are variable and dependent on the environment (i.e. recognition processes) and/or on application parameters (i.e. process frequencies depend on robot speed). In this paper, a real-time mobile robotic architecture to cope with the functional and variable temporal characteristics of behaviour-based mobile robotic applications is proposed. Run-time flexibility is a main feature of the architecture that supports the variability of the temporal characteristics of the workload. The system has to be adapted to the environmental conditions, by adjusting robot control parameters (i.e. speed) or the system load (i.e. computational time), and take actions depending on it. This influence is focused on the ability of the system to select the appropriate activity to be executed depending on the available time, and, to change its behaviour depending on the environmental information. The flexibility of the system is allowed thanks to the definition of a real-time task model and the design of adaptation mechanisms for the regulation of the reactive load. The improvement of the robot quality of service (QoS) is another important aspect discussed in the paper. The architecture incorporates a quality of service manager (QoSM) that allows dynamically monitor analyse and improve the robot performances. Depending on the internal state, on the environment and on the objectives, the robot performance requirements vary (i.e. when the environment is overloaded, global map processes generating high-quality maps are required). The QoSM receives the performance requirements of the robot, and by adjusting the reactive load, the system enables the necessary slack time to schedule the more suitable deliberative processes and hence fulfilling the robot QoS. Moreover, the deliberative load can be scheduled by different heuristic strategies that provide answers of varying quality.

Design principles of digitally controlled robots

The primary mechanical and control parameters of robots are usually determined for design purposes by reference to theories of linear and continuous systems, which provide a simple and attractive engineering approach. However, non-linear phenomena such as the Coulomb friction and backlash, and the effects of digitalccontrol can lead subsequently to long and tedious experimental development. The paper proposes digital methods of design that accomodate these difficulties. Experiments on a special-purpose three degree of freedom robot have confirmed the validity of the approach in that application.