Real-time normal contact force control for robotic surface processing of workpieces without a priori geometric model

2022 ◽  
Author(s):  
Jian Li ◽  
Yisheng Guan ◽  
Haowen Chen ◽  
Bing Wang ◽  
Tao Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Contact Force ◽  
Force Control ◽  
Geometric Model ◽  
A Priori ◽  
Surface Processing ◽  
Normal Contact ◽  
Normal Contact Force ◽  
Contact Force Control

Scanning control based on real-time contact force feedback for ultrasonic thickness measurement

2021 ◽  
pp. 014233122199092
Author(s):  
Haibo Liu ◽  
Xu Li ◽  
Qile Bo ◽  
Meng Lian ◽  
Te Li ◽  
...  
Keyword(s):  
Real Time ◽  
Contact Force ◽  
Force Control ◽  
Sliding Mode ◽  
Variable Structure ◽  
Normal Contact ◽  
Normal Contact Force ◽  
Sliding Mode Variable Structure ◽  
Ultrasonic Thickness ◽  
Contact Force Control

An effective contact force control strategy is of great significance for accurate and stable ultrasonic thickness on-machine measurement. However, it is difficult to adjust the contact force dynamically due to the uncertainty of the geometric characteristics of the measured workpiece. In this paper, a contact force control method based on the combination of adaptive impedance controller and sliding mode variable structure position controller is proposed. First, the control process with the force tracking impedance control and a normal contact force calculation model is established. Then, a force-position conversion model and a sliding mode variable structure controller are proposed. Further, a simulation with a typical S-shaped measured surface is given to show that the algorithm for controlling contact force can achieve good real-time tracking performance and has stronger robustness than traditional methods. Finally, an arc-shaped aluminum alloy thin-wall part thickness is sampled along the scan trajectory to verify the effectiveness of the algorithm. The experimental results show that the proposed algorithm for controlling contact force can quickly adjust the measuring device to the target position and maintain the stability of the normal contact force to ensure the accuracy of ultrasonic thickness on-machine measurement.

scholarly journals Neural Network Based Contact Force Control Algorithm for Walking Robots

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 287
Author(s):  
Byeongjin Kim ◽  
Soohyun Kim
Keyword(s):  
Neural Network ◽  
Contact Force ◽  
Force Control ◽  
Control Algorithm ◽  
Position Control ◽  
Linear Quadratic Regulator ◽  
Walking Robots ◽  
Test Model ◽  
Linear Quadratic ◽  
Contact Force Control

Walking algorithms using push-off improve moving efficiency and disturbance rejection performance. However, the algorithm based on classical contact force control requires an exact model or a Force/Torque sensor. This paper proposes a novel contact force control algorithm based on neural networks. The proposed model is adapted to a linear quadratic regulator for position control and balance. The results demonstrate that this neural network-based model can accurately generate force and effectively reduce errors without requiring a sensor. The effectiveness of the algorithm is assessed with the realistic test model. Compared to the Jacobian-based calculation, our algorithm significantly improves the accuracy of the force control. One step simulation was used to analyze the robustness of the algorithm. In summary, this walking control algorithm generates a push-off force with precision and enables it to reject disturbance rapidly.

Contact Stability and Contact Safety of a Magnetic Resonance Imaging-Guided Robotic Catheter Under Heart Surface Motion

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Ran Hao ◽  
E. Erdem Tuna ◽  
M. Cenk Çavuşoğlu
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Motion Prediction ◽  
Resonance Imaging ◽  
Contact Stability ◽  
Heart Motion ◽  
Control Scheme ◽  
Control Schemes ◽  
Position Feedback ◽  
Contact Force Control

Abstract Contact force quality is one of the most critical factors for safe and effective lesion formation during catheter based atrial fibrillation ablation procedures. In this paper, the contact stability and contact safety of a novel magnetic resonance imaging (MRI)-actuated robotic cardiac ablation catheter subject to surface motion disturbances are studied. First, a quasi-static contact force optimization algorithm, which calculates the actuation needed to achieve a desired contact force at an instantaneous tissue surface configuration is introduced. This algorithm is then generalized using a least-squares formulation to optimize the contact stability and safety over a prediction horizon for a given estimated heart motion trajectory. Four contact force control schemes are proposed based on these algorithms. The first proposed force control scheme employs instantaneous heart position feedback. The second control scheme applies a constant actuation level using a quasi-periodic heart motion prediction. The third and the last contact force control schemes employ a generalized adaptive filter-based heart motion prediction, where the former uses the predicted instantaneous position feedback, and the latter is a receding horizon controller. The performance of the proposed control schemes is compared and evaluated in a simulation environment.

Experimental Validation of a Volumetric Planetary Rover Wheel/Soil Interaction Model

2013 ◽  
Author(s):  
Willem Petersen ◽  
John McPhee
Keyword(s):  
Contact Force ◽  
Interaction Model ◽  
Contact Model ◽  
Soil Parameters ◽  
Model Parameters ◽  
Force Model ◽  
Normal Contact ◽  
Planetary Rover ◽  
Normal Contact Force ◽  
Contact Force Model

For the multibody simulation of planetary rover operations, a wheel-soil contact model is necessary to represent the forces and moments between the tire and the soft soil. A novel nonlinear contact modelling approach based on the properties of the hypervolume of interpenetration is validated in this paper. This normal contact force model is based on the Winkler foundation model with nonlinear spring properties. To fully define the proposed normal contact force model for this application, seven parameters are required. Besides the geometry parameters that can be easily measured, three soil parameters representing the hyperelastic and plastic properties of the soil have to be identified. Since it is very difficult to directly measure the latter set of soil parameters, they are identified by comparing computer simulations with experimental results of drawbar pull tests performed under different slip conditions on the Juno rover of the Canadian Space Agency (CSA). A multibody dynamics model of the Juno rover including the new wheel/soil interaction model was developed and simulated in MapleSim. To identify the wheel/soil contact model parameters, the cost function of the model residuals of the kinematic data is minimized. The volumetric contact model is then tested by using the identified contact model parameters in a forward dynamics simulation of the rover on an irregular 3-dimensional terrain and compared against experiments.

SLIDING MODE CONTACT FORCE CONTROL FOR SLIP PREVENTION IN A ROBOTIC GRIPPER

2009 ◽  
Author(s):  
M. D. O'TOOLE ◽  
K. BOUAZZA-MAROUF ◽  
D. KERR ◽  
M. VLOEBERGHS
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Sliding Mode ◽  
Contact Force Control

Catastrophe Analysis of Planar Three-Spring Systems

1998 ◽  
Author(s):  
J. P. Yin ◽  
D. Marsh ◽  
J. Duffy
Keyword(s):  
Contact Force ◽  
Force Control ◽  
Energy Function ◽  
System A ◽  
Spring System ◽  
Spring Mechanism ◽  
And Control ◽  
Control Tool ◽  
Contact Force Control

Abstract A special planar three-spring mechanism is proposed for contact force control. An energy function is defined to describe the behavior of this kind of mechanism. It can be used to perform the catastrophe analysis of this mechanism. The analysis result can be used as a design and control tool. By comparing the three-spring system and a two-spring system, we found the three-spring mechanism has better stability than the two-spring system. A three-spring mechanism which can be used to control a general contact force in a plane is also analyzed.

Sign in / Sign up

Export Citation Format

Share Document