Verification of a Wheeled Mobile Robot Dynamic Model and Control Ramifications

1999 ◽  
Vol 121 (1) ◽  
pp. 58-63 ◽  
Author(s):  
Daehie Hong ◽  
Steven A. Velinsky ◽  
Xin Feng
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Kinematic Model ◽  
High Load ◽  
Wheeled Mobile Robots ◽  
Model Based Control ◽  
Practical Applications ◽  
High Speeds ◽  
Kinematic Models ◽  
And Control

For low speed, low acceleration, and lightly loaded applications, kinematic models of Wheeled Mobile Robots (WMRs) provide reasonably accurate results. However, as WMRs are designed to perform more demanding, practical applications with high speeds and/or high loads, kinematic models are no longer valid representations. This paper includes experimental results for a heavy, differentially steered WMR for both loaded and unloaded conditions. These results are used to verify a recently developed dynamic model which includes a complex tire representation to accurately account for the tire/ground interaction. The dynamic model is then exercised to clearly show the inadequacy of kinematic models for high load and/or high speed conditions. Furthermore, through simulation, the failure of kinematic model based control for such applications is also shown.

A New Yaw Dynamic Model for Improved High Speed Control of a Farm Tractor

2002 ◽  
Vol 124 (4) ◽  
pp. 659-667 ◽  
Author(s):  
David M. Bevly ◽  
J. Christian Gerdes ◽  
Bradford W. Parkinson
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Kinematic Model ◽  
Second Order ◽  
Lateral Control ◽  
Relaxation Length ◽  
High Speeds ◽  
Farm Tractor ◽  
Bicycle Model ◽  
Higher Order Models

This paper presents the system identification of a new model for the farm tractor’s yaw dynamics in order to improve automatic control at higher speeds and understand controller limitations from neglecting these dynamics. As speed increases, higher order models are required to maintain accurate lateral control of the vehicle. Neglecting these dynamics can cause the controller to become unstable at the bandwidths required for accurate control at higher speeds. The yaw dynamic model, which is found to be dominated by a second order response, is identified for multiple speeds to determine the effect of velocity on the model. The second order yaw dynamics cannot be represented by the traditional bicycle model. An analytical derivation shows that the model characteristics can, however, be captured by a model consisting of a significant (non-negligible) relaxation length in the front tire. Experimental results are presented showing that the new yaw dynamic model can provide lateral control of the tractor to within 4 cm (1σ) at speeds up to 8 m/s. These results are shown to be an improvement, at high speeds, over controllers based on models (such as a kinematic model) previously used for control of farm equipment.

Experimental validation on the integrated design and control of a parallel robot

Robotica ◽  
2005 ◽  
Vol 24 (2) ◽  
pp. 173-181 ◽  
Author(s):  
Qing Li
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Dynamic Models ◽  
Integrated Design ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Approximation Techniques ◽  
Control Approach ◽  
Modeling Errors ◽  
And Control

Due to the demands from the robotic industry, robot structures have evolved from serial to parallel. The control of parallel robots for high performance and high speed tasks has always been a challenge to control engineers. Following traditional control engineering approaches, it is possible to design advanced algorithms for parallel robot control. These approaches, however, may encounter problems such as heavy computational load and modeling errors, to name it a few. To avoid heavy computation, simplified dynamic models can be obtained by applying approximation techniques, nevertheless, performance accuracy will suffer due to modeling errors. This paper suggests applying an integrated design and control approach, i.e., the Design For Control (DFC) approach, to handle this problem. The underlying idea of the DFC approach can be illustrated as follows: Intuitively, a simple control algorithm can control a structure with a simple dynamic model quite well. Therefore, no matter how sophisticate a desired motion task is, if the mechanical structure is designed such that it results in a simple dynamic model, then, to design a controller for this system will not be a difficult issue. As such, complicated control design can be avoided, on-line computation load can be reduced and better control performance can be achieved. Through out the discussion in the paper, a 2 DOF parallel robot is redesigned based on the DFC concept in order to obtain a simpler dynamic model based on a mass-balancing method. Then a simple PD controller can drive the robot to achieve accurate point-to-point tracking tasks. Theoretical analysis has proven that the simple PD control can guarantee a stable system. Experimental results have successfully demonstrated the effectiveness of this integrated design and control approach.

Active Control of a High-Speed Pantograph

1997 ◽  
Vol 119 (1) ◽  
pp. 1-4 ◽  
Author(s):  
D. N. O’Connor ◽  
S. D. Eppinger ◽  
W. P. Seering ◽  
D. N. Wormley
Keyword(s):  
Dynamic Model ◽  
Active Control ◽  
Contact Force ◽  
High Speed ◽  
High Speed Train ◽  
Single Measurement ◽  
Force Variation ◽  
Catenary System ◽  
And Performance ◽  
And Control

The design and performance of an active controller for a pantograph which collects current for a high-speed train are considered. A dynamic model of the pantograph/catenary system is described and control objectives are established. A design which incorporates a frame-actuated controller and requires only a single measurement is described. Over an array of train speeds, the contact force variation with the actively controlled pantograph is 50 percent less than for the equivalent passive pantograph system.

scholarly journals Adaptive Kinematic Modelling for Multiobjective Control of a Redundant Surgical Robotic Tool

Robotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 68
Author(s):  
Francesco Cursi ◽  
George P. Mylonas ◽  
Petar Kormushev
Keyword(s):  
Kinematic Model ◽  
Adaptive Strategy ◽  
Machine Learning Techniques ◽  
Effective Control ◽  
Surgical Robots ◽  
Tracking Errors ◽  
Kinematic Modelling ◽  
Kinematic Models ◽  
Robotic Tool ◽  
And Control

Accurate kinematic models are essential for effective control of surgical robots. For tendon driven robots, which are common for minimally invasive surgery, the high nonlinearities in the transmission make modelling complex. Machine learning techniques are a preferred approach to tackle this problem. However, surgical environments are rarely structured, due to organs being very soft and deformable, and unpredictable, for instance, because of fluids in the system, wear and break of the tendons that lead to changes of the system’s behaviour. Therefore, the model needs to quickly adapt. In this work, we propose a method to learn the kinematic model of a redundant surgical robot and control it to perform surgical tasks both autonomously and in teleoperation. The approach employs Feedforward Artificial Neural Networks (ANN) for building the kinematic model of the robot offline, and an online adaptive strategy in order to allow the system to conform to the changing environment. To prove the capabilities of the method, a comparison with a simple feedback controller for autonomous tracking is carried out. Simulation results show that the proposed method is capable of achieving very small tracking errors, even when unpredicted changes in the system occur, such as broken joints. The method proved effective also in guaranteeing accurate tracking in teleoperation.

Train delay propagation under random interference on high-speed rail network

2019 ◽  
Vol 30 (08) ◽  
pp. 1950059
Author(s):  
Ziyan Feng ◽  
Chengxuan Cao ◽  
Yutong Liu
Keyword(s):  
Dynamic Model ◽  
High Speed ◽  
Sensitivity Analyses ◽  
High Speed Rail ◽  
Control Policies ◽  
Passenger Train ◽  
Delay Propagation ◽  
Rail Network ◽  
Railway Traffic ◽  
And Control

To simulate passenger train movements on the high-speed rail network, this paper proposes a new dynamic model based on the discrete time method and provides some efficient control policies correspondingly. Besides that, an improved minimum safe headway in the moving-block system on the high-speed rail network is presented. Using the proposed method, the dynamic characteristics of railway traffic flow are analyzed under random interferences on the high-speed rail network. Then, some sensitivity analyses are implemented to investigate the propagation features of delays under different interferences. The results indicate that the proposed dynamic model and control policies for the passenger train movements on the high-speed rail network are effective and can be a fundamental research for subsequent research of delay propagation, rerouting and rescheduling problems.

Cylinder Pressure Transients in Oil Hydraulic Pumps with Sliding Plate Valves

1986 ◽  
Vol 200 (1) ◽  
pp. 45-54 ◽  
Author(s):  
K A Edge ◽  
J Darling
Keyword(s):  
High Speed ◽  
Theoretical Models ◽  
High Load ◽  
Cylinder Pressure ◽  
Axial Piston Pump ◽  
Pump Design ◽  
High Speeds ◽  
Port Opening ◽  
Cylinder Bore ◽  
Axial Piston

This paper reports an experimental study of the cylinder pressure within an axial piston pump. This study revealed that existing theoretical models, which are based on the effects of fluid compliance within the cylinder, are highly inaccurate at high speeds or high loads. Fluid momentum at the point of port opening was found to be of considerable importance and an improved digital computer model was developed as an aid to pump design. The inclusion of fluid momentum effects resulted in a significant improvement in the agreement between theory and experiment. Cavitation within the cylinder bore was predicted at both high speed and high load conditions; this was confirmed experimentally. The theoretical approach is applicable to any sliding valve plate unit.

scholarly journals Resonant scanning design and control for fast spatial sampling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhanghao Sun ◽  
Ronald Quan ◽  
Olav Solgaard
Keyword(s):  
High Speed ◽  
Spatial Sampling ◽  
Frame Rate ◽  
Design Rule ◽  
Optimized Design ◽  
Two Dimensional ◽  
Practical Applications ◽  
Physical Constraints ◽  
High Bandwidth ◽  
And Control

AbstractTwo-dimensional, resonant scanners have been utilized in a large variety of imaging modules due to their compact form, low power consumption, large angular range, and high speed. However, resonant scanners have problems with non-optimal and inflexible scanning patterns and inherent phase uncertainty, which limit practical applications. Here we propose methods for optimized design and control of the scanning trajectory of two-dimensional resonant scanners under various physical constraints, including high frame-rate and limited actuation amplitude. First, we propose an analytical design rule for uniform spatial sampling. We demonstrate theoretically and experimentally that by expanding the design space, the proposed designs outperform previous designs in terms of scanning range and fill factor. Second, we show that we can create flexible scanning patterns that allow focusing on user-defined Regions-of-Interest (RoI) by modulation of the scanning parameters. The scanning parameters are found by an optimization algorithm. In simulations, we demonstrate the benefits of these designs with standard metrics and higher-level computer vision tasks (LiDAR odometry and 3D object detection). Finally, we experimentally implement and verify both unmodulated and modulated scanning modes using a two-dimensional, resonant MEMS scanner. Central to the implementations is high bandwidth monitoring of the phase of the angular scans in both dimensions. This task is carried out with a position-sensitive photodetector combined with high-bandwidth electronics, enabling fast spatial sampling at $$\sim 100$$ ∼ 100 Hz frame-rate.

scholarly journals Analysis and control for a new reconfigurable parallel mechanism

2020 ◽  
Vol 17 (5) ◽  
pp. 172988142093132
Author(s):  
Guanyu Huang ◽  
Dan Zhang ◽  
Hongyan Tang ◽  
Lingyu Kong ◽  
Sumian Song
Keyword(s):  
Dynamic Model ◽  
Pid Controller ◽  
Parallel Mechanism ◽  
Screw Theory ◽  
Sliding Mode ◽  
Kinematic Model ◽  
Inverse Kinematic ◽  
Loop Equation ◽  
Lagrange Formulation ◽  
And Control

This article proposes a new reconfigurable parallel mechanism using a spatial overconstrained platform. This proposed mechanism can be used as a machine tool. The mobility is analyzed by Screw Theory. The inverse kinematic model is established by applying the closed-loop equation. Next, the dynamic model of the presented mechanism is established by Lagrange formulation. To control the presented mechanism, some controllers have been used. Based on this dynamic model, the fuzzy-proportion integration differentiation (PID) controller is designed to track the trajectory of the end effector. For each limb, a sliding mode controller is applied to track the position and velocity of the slider. Finally, some simulations using ADAMS and MATLAB are proposed to verify the effectiveness and stability of these controllers.

Kinematic Model of Nonholonomic Mobile Robots

2014 ◽  
Vol 611 ◽  
pp. 107-114 ◽  
Author(s):  
Jaromír Jezný
Keyword(s):  
Mobile Robots ◽  
Structural Characteristics ◽  
Kinematic Model ◽  
Wheeled Mobile Robots ◽  
Nonholonomic Mobile Robots ◽  
General Overview ◽  
Kinematic Models ◽  
Multiple Groups

Provided in this article is a general overview of modeling nonholonomic mobile robots. Emphasis is given to the structural characteristics of kinematic models, taking into account the mobility restrictions caused by various links. Based on the degree of mobility and the degree of controllability it is possible to divide wheeled mobile robots into multiple groups, regardless of the robot construction and the wheels arrangement.

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