Angular Acceleration Control Research Articles

Onboard actuator model-based Incremental Nonlinear Dynamic Inversion for quadrotor attitude control: Method and application

This paper addresses the robust attitude control problem for quadrotors subject to model mismatch and disturbances. A dynamic inversion based attitude control scheme is proposed, which consists of an outer loop attitude controller and an inner loop angular acceleration controller. The attitude controller is designed based on the Nonlinear Dynamic Inversion (NDI) to precisely linearize the nonlinear dynamics between the angular acceleration and the attitude. An onboard actuator model-based Incremental Nonlinear Dynamic Inversion (INDI) controller is designed in the angular acceleration control loop to improve the robustness against the model mismatch and disturbances. Meanwhile, the onboard actuator model with a modified structure eliminates the oscillation phenomenon when the sampling rate of the controller is higher than that of the actuator. Numerical simulations and flight tests demonstrate the effectiveness and robustness of the proposed controller in comparison with the PID controller.

Attitude control of tiltwing aircraft using a wing-fixed coordinate system and incremental nonlinear dynamic inversion

In this paper, we present a novel concept for robustly controlling the attitude of tiltwing aircraft. Our main contribution is the introduction of a wing-fixed coordinate system for angular acceleration control, which forms the basis of a simple and robust attitude controller. Using the wing-fixed coordinate system allows us to describe the actuator effectivity using simple approximations based on the current operating conditions of the aircraft. Coupled with a robust angular rate control concept, which does not rely on an accurate aerodynamic model, we present a controller stabilizing the entire flight envelope of a tiltwing aircraft. The underlying angular acceleration controller uses the concept of Incremental Nonlinear Dynamic Inversion (INDI) to achieve robustness against aerodynamic uncertainties. The resulting controller is evaluated in both simulation studies and flight tests.

Simulation of Angular Acceleration Control for Information Acquisition Robots with Air-Ground Purpose

Simulation of Angular Acceleration Control for Information Acquisition Robots with Air-Ground Purpose

Contact Force Control of Quadrotor Based on Rotor Angular Acceleration Control

Contact Force Control of Quadrotor Based on Rotor Angular Acceleration Control

Relaxing Nonholonomic Constraints to Eliminate Chattering From Time-Optimal Control Solutions

This letter presents a new approach to tackle the problem of infinite chattering , observed at bang-singular junctions of the minimum-time trajectories of car-like robots with bounded angular acceleration control. To eliminate chattering from time-optimal control solutions, we propose to relax the ideal nonholonomic constraint of no-skidding. A proof is presented to demonstrate that this relaxation eliminates chattering from the bang-singular junctions. Finally, a solution to the time-optimal synthesis under the condition of small skid angles is provided.

Design and Control of a Hydraulic Simulator for a Flexible-Joint Robot

For the first time, a novel experimental hydraulic system that simulates joint flexibility of a single-rigid-link flexible-joint robot manipulator, with the ability of changing the joint flexibility's parameters, was designed and implemented in this study. Such a system could facilitate future control studies of robot manipulators by reducing investigation time and implementation cost of research. It could also be used to test the performance of different strategies to control the movement of flexible-joint manipulators. A hydraulic rotary servo motor was used to simulate the action of a flexible-joint robot manipulator, which was a challenging task, since the control of angular acceleration was required. In this study, a single-rigid-link elastic-joint robot manipulator was mathematically modeled and implemented in which joint flexibility parameters such as stiffness and damping could be easily changed. This simulation is referred to as a 'function generator' to drive a hydraulic robot manipulator. In this study the desired angular acceleration of the manipulator was used as the input to the hydraulic rotary motor and the objective was to make the hydraulic system follow the desired acceleration in the frequency range specified. A hydraulic actuator robot was built and tested. The results indicated that if the input signal had a frequency in the range of 5–15 Hz and damping ratio of 0.1 (typical values for flexible joints), the experimental setup was able to reproduce the input signal with acceptable accuracy. Owing to the inherent noise associated with the measurement of acceleration and some severe nonlinearities in the rotary motor, control of the experimental test system using classical methods was a challenging task that had not been anticipated.

Description of the SD-1 high-speed axial rotation device.

A high-speed axial rotation device capable of carrying animal subjects, the SD-1, was constructed and evaluated for vestibular research at the University of Iowa. The device can be controlled automatically by using a Data-Trak curve-follower programmer, or manually if desired. The drive system for the device is a Schaevitz GSD2PR variable-speed motor with associated electronic components, including a solid-state power supply with excellent voltage regulation capability. The rotating module is dynamically balanced to insure maximum performance and personal safety. Above 50 degrees/sec, angular velocity of the device increases linearly with increases in setting of the speed-control potentiometer. Control of angular velocity can be maintained constant ±0.20% for any specific setting of the speed-control potentiometer. Control of angular acceleration and deceleration is excellent over the range from 1 degree/sec2 to 3 × 103 degrees/sec2. By utilizing either the programmer or plugging unit, angular acceleratio...