SOFT FOOD ROBOTIC PICK AND PLACE OPERATION WITH EMBEDDED CONTROL STRUCTURE

2013 ◽  
Vol 37 (3) ◽  
pp. 273-282
Author(s):  
Shiuh-Jer Huang ◽  
Wei-Han Chang ◽  
Janq-Yann Lin

Robotic pick-and-place operation is planned for handling hard objects with on-off control gripper. It does not have force monitoring capability for safe grasping soft objects. Current force/torque sensor is too expensive and difficult to implement. Here, a low cost embedded control structure is designed with distributed FPGA robotic position control and gripper Arduino force control kernels. A model-free intelligent fuzzy sliding mode control strategy is employed to design the position controller of each robotic joint and gripper force controller. Experimental results show that the position and force tracking control errors of this robotic system are less than 1 mm and 0.1 N, respectively for pick-and-place different soft foods.

2013 ◽  
Vol 284-287 ◽  
pp. 1841-1845
Author(s):  
Shiuh Jer Huang ◽  
Wei Han Chang ◽  
Janq Yann Lin

Here a low cost embedded robotic gripper with force control function is designed for frangible fruit manipulation. This embedded control gripper is integrated with a Mitsubishi robot based on FPGA control structure. The model-free intelligent fuzzy sliding mode control strategy is employed to design the position controller of each joint and gripper force controller, respectively. Experimental results of pick-and-place frangible small tomato and banana fruit are shown by pictures to evaluate this embedded position/force hybrid control system performance.


2013 ◽  
Vol 753-755 ◽  
pp. 2006-2009 ◽  
Author(s):  
Shiuh Jer Huang ◽  
Wei Han Chang ◽  
Jui Yiao Su

Although, on-off control robot gripper is widely employed in pick-and-place operations, it can not be applied in fragile or soft objects handling. Here, an intelligent gripper is designed with embedded distributed control structure for overcoming the uncertainty of grasped object mass and soft/hard features. An efficient model-free intelligent fuzzy sliding mode control strategy is employed to design the position and force controllers of gripper, respectively. Experimental results of pick-and-place soft and hard objects with grasping force auto-tuning and anti-slip control strategy are shown by pictures to verify this distributed system performance. The position and force tracking errors are less than 1 mm and 0.1 N, respectively.


2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Ji Min Lee ◽  
Sung Hwan Park ◽  
Jong Shik Kim

A robust control scheme is proposed for the position control of the electrohydrostatic actuator (EHA) when considering hardware saturation, load disturbance, and lumped system uncertainties and nonlinearities. To reduce overshoot due to a saturation of electric motor and to realize robustness against load disturbance and lumped system uncertainties such as varying parameters and modeling error, this paper proposes an adaptive antiwindup PID sliding mode scheme as a robust position controller for the EHA system. An optimal PID controller and an optimal anti-windup PID controller are also designed to compare control performance. An EHA prototype is developed, carrying out system modeling and parameter identification in designing the position controller. The simply identified linear model serves as the basis for the design of the position controllers, while the robustness of the control systems is compared by experiments. The adaptive anti-windup PID sliding mode controller has been found to have the desired performance and become robust against hardware saturation, load disturbance, and lumped system uncertainties and nonlinearities.


2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jing He ◽  
Changfan Zhang

A design scheme that integrates fault reconfiguration and fault-tolerant position control is proposed for a nonlinear servo system with friction. Analysis of the non-linear friction torque and fault in the system is used to guide design of a sliding mode position controller. A sliding mode observer is designed to achieve fault reconfiguration based on the equivalence principle. Thus, active fault-tolerant position control of the system can be realized. A real-time simulation experiment is performed on a hardware-in-loop simulation platform. The results show that the system reconfigures well for both incipient and abrupt faults. Under the fault-tolerant control mechanism, the output signal for the system position can rapidly track given values without being influenced by faults.


Author(s):  
Chen Su ◽  
Ao Chai ◽  
Xikai Tu ◽  
Hongyu Zhou ◽  
Haiqiang Wang ◽  
...  

Nerve injury can cause lower limb paralysis and gait disorder. Currently lower limb rehabilitation exoskeleton robots used in the hospitals need more power to correct abnormal motor patterns of stroke patients’ legs. These gait rehabilitation robots are powered by cumbersome and bulky electric motors, which provides a poor user experience. A newly developed gait rehabilitation exoskeleton robot actuated by low-cost and lightweight pneumatic artificial muscles (PAMs) is presented in this research. A model-free proxy-based sliding mode control (PSMC) strategy and a model-based chattering mitigation robust variable control (CRVC) strategy were developed and first applied in rehabilitation trainings, respectively. As the dynamic response of PAM due to the compressed air is low, an innovative intention identification control strategy was taken in active trainings by the use of the subject’s intention indirectly through the estimation of the interaction force between the subject’s leg and the exoskeleton. The proposed intention identification strategy was verified by treadmill-based gait training experiments.


Author(s):  
Habib Bhuiyan ◽  
Jung-Hyo Lee

This paper proposes a position control method for low cost EGR valve system in automotive application. Generally, position control system using in automotive application has many restrictions such as cost and space, the mechanical structure of actuator implies high friction and large difference between static friction and coulomb friction. This large friction difference occurs the vibrated position control result when the controller uses conventional linear controller such as P, PI. In this paper, low cost position control method which can apply under the condition of high difference friction mechanical system. Proposed method is verified by comparing conventional control result of experiments.


Author(s):  
A. Mohamed Nazeer ◽  
S. Sasikala ◽  
A. Kamalabharathy ◽  
S. D. Kirubha Dharshni ◽  
M. Nandhini Lakshmi ◽  
...  

Robots are used in various industries to save the process flow in terms of time and ease. It also improves the process quality of the processed object by reducing the errors. The cost of manufacturing can also be minimized. The proposed system will identify and sort the colour of the yawn in a particular colouring sequence, which is defined in the program. The robot identifies the colour, based on the input given in the keypad. It also picks the object from a source table and place it in a desired destination and vice versa. This Paper aims to select the particular coloured yawn to use it in the machineries. The robot will do pick and place operation by mechanical devices such as gripper and robotic arm. It is carried out on a low cost robot platform for development of pick and place the things. The robot act under the direct control of human or autonomously under the control of the programmed system.


Author(s):  
Ganapathy Ram ◽  
Santha K R

Permanent magnet synchronous motors (PMSMs) are increasingly used in high performance variable speed drives of many industrial applications. PMSM has many features, like high efficiency, compactness, high torque to inertia ratio, rapid dynamic response, simple modeling and control, and maintenance free operation. Presence of position sensors presents several disadvantages, such as reduced reliability, susceptibility to noise, additional cost and weight and increased complexity of the drive system. For these reasons, the development of alternative indirect methods for speed and position control becomes an important research topic. Advantages of sensorless control are reduced hardware complexity, low cost, reduced size, cable elimination, increased noise immunity, increased reliability and decreased maintenance. The key problem in sensorless vector control of ac drives is the accurate dynamic estimation of the stator flux vector over a wide speed range using only terminal variables (currents and voltages). The difficulty comprises state estimation at very low speeds where the fundamental excitation is low and the observer performance tends to be poor. Moreover, the noises of system and measurements are considered other main problems. This paper presents a comprehensive study of the different sliding mode observer methods of speed and position estimations for sensorless control of PMSM drives.


2020 ◽  
Vol 10 (8) ◽  
pp. 2755
Author(s):  
Fang Peng ◽  
Haiyang Wen ◽  
Cheng Zhang ◽  
Bugong Xu ◽  
Jiehao Li ◽  
...  

Active prosthetic knees (APKs) are widely used in the past decades. However, it is still challenging to make them more natural and controllable because: (1) most existing APKs that use rigid actuators have difficulty obtaining more natural walking; and (2) traditional finite-state impedance control has difficulty adjusting parameters for different motions and users. In this paper, a flexible APK with a compact variable stiffness actuator (VSA) is designed for obtaining more flexible bionic characteristics. The VSA joint is implemented by two motors of different sizes, which connect the knee angle and the joint stiffness. Considering the complexity of prothetic lower limb control due to unknown APK dynamics, as well as strong coupling between biological joints and prosthetic joints, an adaptive robust force/position control method is designed for generating a desired gait trajectory of the prosthesis. It can operate without the explicit model of the system dynamics and multiple tuning parameters of different gaits. The proposed model-free scheme utilizes the time-delay estimation technique, sliding mode control, and fuzzy neural network to realize finite-time convergence and gait trajectory tracking. The virtual prototype of APK was established in ADAMS as a testing platform and compared with two traditional time-delay control schemes. Some demonstrations are illustrated, which show that the proposed method has superior tracking characteristics and stronger robustness under uncertain disturbances within the trajectory error in ± 0 . 5 degrees. The VSA joint can reduce energy consumption by adjusting stiffness appropriately. Furthermore, the feasibility of this method was verified in a human–machine hybrid control model.


2010 ◽  
Vol 5 (1-2) ◽  
pp. 249-253
Author(s):  
János Gyeviki ◽  
József Sárosi ◽  
Antal Véha ◽  
Péter Toman

As an important driver element, the pneumatic artificial muscle (PAM) is widely used in industrial applications for many automation purposes thanks to their variety of advantages. The design of a stable robust position controller for PAM is difficult since it is a very nonlinear time-variant controlled plant because of the compressibility of air, air mass flow rate through the valve, etc. The main contribution of this paper is a robust position control method based on sliding mode for pneumatic muscle actuator. Finally, it presents experimental results.


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