PID Motion Controller Research Articles

Precise motion control for a space mining robot based on improved African vultures optimization

Space mining robots can develop and utilize abundant mineral resources in the outer space to solve the problem of the depletion of earth mineral resources. However, the motion errors of space mining robots in complex environments on the outer space surface of asteroids greatly hinder its applications. To bridge this research gap, a precise motion controller of the space mining robot is proposed in this study. Firstly, the kinematics model of robot’s wheels and the whole vehicle dynamics model in soft soil are established. Then, the optimal PID motion controller is developed based on the improved African vultures optimization algorithm (IAVOA). The Henon chaotic mapping, nonlinear adaptive incremental inertial weight factor and reverse learning competition strategy are introduced to optimize the initial population position, position update method and optimal solution output, respectively. Meanwhile, the excellent optimization performance of IAVOA is also validated by test results of nine benchmark functions. Lastly, the performance of controller is verified by simulations and experiments. The simulation results show that the proposed IAVOA-PID controller is superior to the original PID and AVOA-PID controller with faster response time and smaller overshoot. The experiment results show the space mining robot with the assistance of proposed motion controller can move with a trajectory error of less than 0.2 m and a motion error of less than 0.01 m.

A New Self-Tuning Nonlinear PID Motion Control for One-Axis Servomechanism with Uncertainty Consideration

This paper introduces a new study for one-axis servomechanism with consideration the parameter variation and system uncertainty. Also, a new approach for high-performance self-tuning nonlinear PID control was developed to track a preselected profile with high accuracy. Moreover, a comparison study between the proposed control technique and the well-known controllers (PID and Nonlinear PID). The optimal control parameters were determined based on the COVID-19 optimization technique. The parameters of the servomechanism system changed randomly at a preselected range through the online simulation. The change of these parameters acts as the nonlinearity resources (friction, backlash, environmental effects) and system uncertainty. A comparative study between the linear and nonlinear models had been accomplished and investigated. The results show that the proposed controller can track several operating points with high accuracy, low rise time, and small overshoot.

Application of Fuzzy PID Position Control Algorithm in Motion Control System Design of Palletizing Robot

In view of the low efficiency in traditional palletizing robot problem of poor control precision, this paper introduces fuzzy PID position control algorithm, based on the actual operation situation of palletizing robot; determined as palletizing robot FPGA hardware platform, hardware platform based on this fuzzy PID position control algorithm is applied to implement palletizing robot motion control system design. The simulation model of fuzzy PID motion control was established by MATLAB software for testing to determine that the fuzzy PID position control algorithm reflects the time quickly in the motion control of palletizing robot, and the actual overshooting is small, which is more suitable for the motion control algorithm of palletizing robot. Under this condition, the modular method is adopted to complete the system application design on the FPGA hardware platform.

Grinding Force Control of Polishing Cubic Zirconia Gem by an Automatic Faceting Machine

This research work is to develop a controller that combines the position and indirect force control for the gemstone polishing process. The polished gemstones are attached to the end of drop-stick of the Chula Automatic Faceting Machine. The Chula Automatic Faceting Machine has 4-axis high precision motion control and the other 2-axis for spindle and crank motion. Many gemstones (number of gemstones will depends on the size of the gemstone) can be grinded and polished simultaneously with the result of uniform size and quality. In this research work, the controller is developed based on PID motion control. The reference position of the controller for the grinding process is obtained based on the compliance force control technique with known compliance model. This reference position will specified the pressing force for the grinding process indirectly. The controller developed in-house is used for testing with Cubic Zirconia gemstone which the hardness is 8.5 Mohs. The compliance model and appropriate parameters including the minimum and maximum boundary of polishing process can be obtained experimentally. Then all parameters obtained from the experiment can be used in the controller. The uniform size and quality of the multi-stone grinding and polishing process can be obtained with this controller.

Motion control systems with ℋ/sup ∞/ positive joint torque feedback

In this work, a new /spl Hscr//sup /spl infin// joint torque feedback approach is proposed which takes into account the actuator's finite bandwidth dynamics, and minimizes the system's sensitivity to load torque disturbances and load dynamics. We also address implementation issues such as the development of a hydraulic dynamometer testbed for measurement of the disturbance sensitivity and of an innovative method for identifying the actuator dynamics. Experiment results with our experimental direct-drive motor demonstrate that the additional /spl Hscr//sup /spl infin// positive torque feedback greatly improves the disturbance attenuation and load decoupling properties of a simple PID motion controller. The optimal torque feedback also reduces the tracking error when dealing with a dynamic load while, unlike the conventional unity joint torque feedback, maintaining robust stability.

Design of a Robust H∞ PID Control for Industrial Manipulators

Industrial manipulators are under various limitations against high quality motion control; for example, both frictional and dynamic disturbances should be dealt with a simple PID control structure. A robust linear PID motion controller, called the reference error feedback (REF), is proposed, which solves the nonlinear L2-gain attenuation control problem for robotic manipulators. The stability, robustness, and performance tuning of the proposed controller are analyzed. Making use of the fact that the single parameter of the induced L2-gain γ controls the performance with stability attained, we propose a simple and stable method of performance tuning called “the square law.” The analytical results are verified through experiments of a six-degrees-of-freedom industrial manipulator. [S0022-0434(00)00104-0]