Force Control System for Autonomous Micro Manipulation

2002 ◽  
Vol 14 (3) ◽  
pp. 212-220 ◽  
Author(s):  
Tamio Tanikawa ◽  
◽  
Masashi Kawai ◽  
Noriho Koyachi ◽  
Tatsuo Arai ◽  
...  

A dexterous micro manipulation system was developed for applications such as assembling micro machines, manipulating cells, and micro surgery. We have proposed a concept of a two-fingered micro hand, designed and built a prototype. We succeeded in performing basic micro manipulations with a teleoperation, including the grasp, release, and rotation of a microscopic object. The micro hand is controlled with a position control only. An operator has to guess a micro grasping force on the object from a microscope image. The accurate micro manipulation depends on a skill of the operator yet. For an easy manipulation and an automatic manipulation, it is necessary to measure the micro forces between the finger and the object. A micro force sensor has developed for a force control in micro manipulation on a corroboration research of AIST and Olympus Optical Co., Ltd. Its resolution is 0.5 nN in theoretically. In this paper, we will mention the micro force sensor and to perform an automatic micro manipulation with installing the sensor and a force control system. Basic experiment shows excellent micro capability.

2014 ◽  
Vol 614 ◽  
pp. 175-178
Author(s):  
Ming Hua Luo ◽  
Chun Wei Pan ◽  
Xiu Wen Yang ◽  
Xin Hua Luo

This paper proposed a new grasping method for robot fingers with three-axis force sensors. When a robot hand with two fingers is grasping an object, such as an egg, two closed loops with negative feedback in force-control system are start. When grasping force of the two fingers are equal reference force, dynamic balance is reached. Once tiny sliding between egg and finger occurred, force feedback start immediately, dynamic balance is reached again. In this way, our robot hand can firmly grasps eggs, even if vibration added on the robot hand.


2013 ◽  
Vol 284-287 ◽  
pp. 1856-1861
Author(s):  
Hung I Chen ◽  
Ming Chang Shih

In this paper, the pneumatic driven manipulation system is driven by the pneumatic cylinders. The proposed system is built by the designed pneumatic force control system and the microscope, which is integrated with the control interface. Firstly, the characteristics of the pneumatic force control system are measured as the proportional pressure control valve. In accordance with these nonlinear characteristics, a self tuning fuzzy controller with a dead zone compensator is designed to improve precision of the pneumatic force control system. From experimental results, the force error can be controlled within ±1 mN. Next, the real-time image is captured by the microscope with a 1/2 type CCD camera. Through designed image processing, image tracking and image recognition, visual image is used to define the position a probe tip. The distance between the target position and a probe tip can be calculated. Finally, the force control of the pneumatic force control system, calculating the distance between the target position and a probe tip, the control processes are integrated with designed the control interface. Visual C++ code from MFC is used to finish the control interface. From experimental results, the position error can be controlled within ± 1 pixel.


1995 ◽  
Vol 7 (5) ◽  
pp. 410-418 ◽  
Author(s):  
Guoguang Zhang ◽  
◽  
Junji Furusho ◽  
Akihito Sano ◽  

Force control using a hierarchical structure is discussed, which consists of upper force control and lower joint position control. The force controller calculators the joint position corrections necessary to control the force in the desired manner. These correction signals from the force controller are output to the lower controller and added to the nominal joint position command. In this paper, we apply mixed sensitivity design of H∞ control theory to a force control system. The nominal model is discussed, and the robustness against modeling error is analyzed. Owing to joint torque feedback control, the change of the controlled plant is reduced, so high gain force control can be achieved. Experimental results and eigenvalue analysis are also presented.


Author(s):  
Mark J. McKay ◽  
Hodge E. Jenkins

The ability to precisely control the applied force and deformation of a grasped object is the focus of this paper. A simple mechanical end effector system with parallel grippers was developed to study compliance effects in precision grasping. A servo gripper was instrumented with force and position sensors, associated circuitry, hardware, and visual indicators; moreover, the sensors and servo motor were connected to a microcontroller that interfaced with a laptop computer. A closed-loop position control system was embedded within a force control system. Springs of varying, known stiffness were grasped to characterize and calibrate the force control system. Compliance effects of the servo gripper were observed and measured while grasping these springs under several discrete control conditions. Experimental data were compared to reduced order theoretical models for validation. A control scheme was successfully developed to precisely grasp and hold objects of varying size, shape, stiffness, and orientation, using the real-time data to establish correction factors for compliance and sensor drift. It was demonstrated that these effects can be minimized by modifying the motor control signals using the presented force and position feedback scheme.


Author(s):  
K. Shibazaki ◽  
H. Nozaki

In this study, in order to improve steering stability during turning, we devised an inner and outer wheel driving force control system that is based on the steering angle and steering angular velocity, and verified its effectiveness via running tests. In the driving force control system based on steering angle, the inner wheel driving force is weakened in proportion to the steering angle during a turn, and the difference in driving force is applied to the inner and outer wheels by strengthening the outer wheel driving force. In the driving force control (based on steering angular velocity), the value obtained by multiplying the driving force constant and the steering angular velocity,  that differentiates the driver steering input during turning output as the driving force of the inner and outer wheels. By controlling the driving force of the inner and outer wheels, it reduces the maximum steering angle by 40 deg and it became possible to improve the cornering marginal performance and improve the steering stability at the J-turn. In the pylon slalom it reduces the maximum steering angle by 45 deg and it became possible to improve the responsiveness of the vehicle. Control by steering angle is effective during steady turning, while control by steering angular velocity is effective during sharp turning. The inner and outer wheel driving force control are expected to further improve steering stability.


2021 ◽  
Vol 21 (2) ◽  
pp. 1-22
Author(s):  
Chen Zhang ◽  
Zhuo Tang ◽  
Kenli Li ◽  
Jianzhong Yang ◽  
Li Yang

Installing a six-dimensional force/torque sensor on an industrial arm for force feedback is a common robotic force control strategy. However, because of the high price of force/torque sensors and the closedness of an industrial robot control system, this method is not convenient for industrial mass production applications. Various types of data generated by industrial robots during the polishing process can be saved, transmitted, and applied, benefiting from the growth of the industrial internet of things (IIoT). Therefore, we propose a constant force control system that combines an industrial robot control system and industrial robot offline programming software for a polishing robot based on IIoT time series data. The system mainly consists of four parts, which can achieve constant force polishing of industrial robots in mass production. (1) Data collection module. Install a six-dimensional force/torque sensor at a manipulator and collect the robot data (current series data, etc.) and sensor data (force/torque series data). (2) Data analysis module. Establish a relationship model based on variant long short-term memory which we propose between current time series data of the polishing manipulator and data of the force sensor. (3) Data prediction module. A large number of sensorless polishing robots of the same type can utilize that model to predict force time series. (4) Trajectory optimization module. The polishing trajectories can be adjusted according to the prediction sequences. The experiments verified that the relational model we proposed has an accurate prediction, small error, and a manipulator taking advantage of this method has a better polishing effect.


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