scholarly journals Detection and Control of Contact Force Transients in Robotic Manipulation Without a Force Sensor

2018 ◽  
Author(s):  
Martin Karlsson ◽  
Anders Robertsson ◽  
Rolf Johansson
Keyword(s):  
Contact Force ◽  
Force Sensor ◽  
Robotic Manipulation ◽  
And Control

Active Compensation Control of Wind Force and Wire Roughness for Current Collector Using Optical Fiber Sensor

1999 ◽  
Author(s):  
Kazuo Yoshida ◽  
Masaaki Ukita ◽  
Toshiaki Makino
Keyword(s):  
Control System ◽  
Optical Fiber ◽  
Active Control ◽  
Contact Force ◽  
Optical Fiber Sensor ◽  
Current Collector ◽  
Low Noise ◽  
Fiber Sensor ◽  
Noise Current ◽  
And Control

Abstract For railways speed up such as 350km/h, it is particularly important to reduce noise caused by current collector for environmental problem. For a solution, a diamond shaped low-noise current collector has been developed. However, it becomes difficult for the current collector to maintain the predetermined contact force between the contact strip and the trolley-wire. Therefore, it is necessary to apply the active control to keep the contact force uniform. However, there is a serious problem for the active control that it is difficult to put sensors in high voltage region. In this paper, an application of plastic optical fiber sensor is devised and it is applied to the control system. In the experiment, the usefulness of the proposed sensor and control system is demonstrated.

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.

scholarly journals Development and Application of a Tandem Force Sensor

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 6042
Author(s):  
Zhijian Zhang ◽  
Youping Chen ◽  
Dailin Zhang
Keyword(s):  
Contact Force ◽  
Mechanical Model ◽  
Traction Force ◽  
Force Sensor ◽  
Teaching Experiment ◽  
Contact Forces ◽  
Contact Tasks

In robot teaching for contact tasks, it is necessary to not only accurately perceive the traction force exerted by hands, but also to perceive the contact force at the robot end. This paper develops a tandem force sensor to detect traction and contact forces. As a component of the tandem force sensor, a cylindrical traction force sensor is developed to detect the traction force applied by hands. Its structure is designed to be suitable for humans to operate, and the mechanical model of its cylinder-shaped elastic structural body has been analyzed. After calibration, the cylindrical traction force sensor is proven to be able to detect forces/moments with small errors. Then, a tandem force sensor is developed based on the developed cylindrical traction force sensor and a wrist force sensor. The robot teaching experiment of drawer switches were made and the results confirm that the developed traction force sensor is simple to operate and the tandem force sensor can achieve the perception of the traction and contact forces.

Feedback Controlled Optomechanical Force Sensor

2011 ◽  
Author(s):  
Jon R. Pratt ◽  
Paul Wilkinson ◽  
Gordon Shaw
Keyword(s):  
Dynamic Properties ◽  
Force Sensor ◽  
Low Noise ◽  
Atomic Scale ◽  
Photon Momentum ◽  
Cantilever Deflection ◽  
Power Intensity ◽  
Intensity Modulated ◽  
And Control ◽  
Excited Oscillator

We present a new servo controllable force sensor that exploits photon momentum forces for the identification, calibration, and control of its dynamic properties. The sensor comprises a millimeter-scale glass cantilever, a low-noise fiber interferometer for detection of the cantilever deflection, and a high-power, intensity-modulated fiber laser to apply optical actuation forces. Combined with appropriate digital and analog signal processing, the sensor has been operated as a feedback-cooled low-noise force sensor, and as a self-excited oscillator governed by the familiar Rayleigh equation. Operated in this self-excited Quber mode, it appears well suited for noncontact, frequency modulated force gradient detection such as in atom discrimination. Here, we briefly lay out the principles of the sensor and provide examples of its performance, including the demonstration of feedback cooling and the ability to induce controlled limit cycle oscillations with atomic scale amplitudes.

Design and Analysis of a Multimodal Grasper Having Shape Conformity and Within-Hand Manipulation With Adjustable Contact Forces

2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Nagamanikandan Govindan ◽  
Asokan Thondiyath
Keyword(s):  
Control Strategies ◽  
Low Cost ◽  
Active Surface ◽  
Force Sensor ◽  
Contact Forces ◽  
Geometrical Shape ◽  
Planning And Control ◽  
Control Scheme ◽  
And Control ◽  
Compact Mechanism

Abstract This paper presents the design, analysis, and testing of a novel multimodal grasper having the capabilities of shape conformation, within-hand manipulation, and a built-in compact mechanism to vary the forces at the contact surface. The proposed grasper has two important qualities: versatility and less complexity. The former refers to the ability to grasp a range of objects having different geometrical shape, size, and payload and perform in-hand manipulations such as rolling and sliding, and the latter refers to the uncomplicated design, and ease of planning and control strategies. Increasing the number of functions performed by the grasper to adapt to a variety of tasks in structured and unstructured environments without increasing the mechanical complexity is the main interest of this research. The proposed grasper consists of two hybrid jaws having a rigid inner structure encompassed by a flexible, active gripping surface. The flexibility of the active surface has been exploited to achieve shape conformation, and the same has been utilized with a compact mechanism, introduced in the jaws, to vary the contact forces while grasping and manipulating an object. Simple and scalable structure, compactness, low cost, and simple control scheme are the main features of the proposed design. Detailed kinematic and static analysis are presented to show the capability of the grasper to adjust and estimate the contact forces without using a force sensor. Experiments are conducted on the fabricated prototype to validate the different modes of operation and to evaluate the advantages of the proposed concept.

Contact force detection and control for robotic polishing based on joint torque sensors

2020 ◽  
Vol 107 (5-6) ◽  
pp. 2745-2756 ◽  
Author(s):  
Yunfei Dong ◽  
Tianyu Ren ◽  
Kui Hu ◽  
Dan Wu ◽  
Ken Chen
Keyword(s):  
Contact Force ◽  
Joint Torque ◽  
Force Detection ◽  
And Control

scholarly journals Parareal with a learned coarse model for robotic manipulation

2020 ◽  
Vol 23 (1-4) ◽  
Author(s):  
Wisdom Agboh ◽  
Oliver Grainger ◽  
Daniel Ruprecht ◽  
Mehmet Dogar
Keyword(s):  
Time Integration ◽  
Robotic Manipulation ◽  
Multiple Objects ◽  
Initial State ◽  
Link Type ◽  
Planning And Control ◽  
Physics Model ◽  
Coarse Model ◽  
Computational Bottleneck ◽  
And Control

AbstractA key component of many robotics model-based planning and control algorithms is physics predictions, that is, forecasting a sequence of states given an initial state and a sequence of controls. This process is slow and a major computational bottleneck for robotics planning algorithms. Parallel-in-time integration methods can help to leverage parallel computing to accelerate physics predictions and thus planning. The Parareal algorithm iterates between a coarse serial integrator and a fine parallel integrator. A key challenge is to devise a coarse model that is computationally cheap but accurate enough for Parareal to converge quickly. Here, we investigate the use of a deep neural network physics model as a coarse model for Parareal in the context of robotic manipulation. In simulated experiments using the physics engine Mujoco as fine propagator we show that the learned coarse model leads to faster Parareal convergence than a coarse physics-based model. We further show that the learned coarse model allows to apply Parareal to scenarios with multiple objects, where the physics-based coarse model is not applicable. Finally, we conduct experiments on a real robot and show that Parareal predictions are close to real-world physics predictions for robotic pushing of multiple objects. Code (https://doi.org/10.5281/zenodo.3779085) and videos (https://youtu.be/wCh2o1rf-gA) are publicly available.

Sign in / Sign up

Export Citation Format

Share Document