Sarbari Datta

Biomimetic Behavior of IPMC Using EMG Signal for Micro Robot

This paper presents the biomimetic behavior of an ionic polymer metal composite (IPMC) based artificial finger for micro robot which can be applicable in holding the object. In this work, IPMC based artificial finger is actuated by controlled electromyographic (EMG) signal. The EMG signal is taken from human index finger via EMG sensor. This signal is pre-amplified before transferring to IPMC for achieving the large bending behavior of IPMC. The biomimetic actuation behavior of IPMC is studied by movement of index finger muscles through long tendons. The stability analysis of EMG signal from human index finger is carried out by providing the proportional–integral–derivative (PID) control system. Experimentally, it is observed that IPMC finger can hold the micro component when IPMC finger is activated through EMG via human muscles and an IPMC based micro gripper is demonstrated.

AMR Vision System for Perception, Job Detection and Identification in Manufacturing

Autonomous mobile robots are becoming an integral part of flexible manufacturing system especially for material transport, cleaning and assembly purpose. The advantage of this type of robots is that the existing manufacturing environment need not be altered or modified as in case of conventional AGVs where permanent cable layouts or markers are required for navigation. These robots are also used extensively for survey, inspection, surveillance, bomb and mine disposal, underwater inspection and space robotics. For autonomous navigation, proprioceptive and exteroceptive sensors are mounted on these mobile robots. As proprioceptive sensors measure the kinematic states of the robot, they accrue error over time and they are supplemented by exteroceptive sensors like ultrasonic and laser range finders, camera and global positioning systems that provide knowledge of its local environment which the robot subsequently uses to navigate. Here we describe the vision system of first indigenous autonomous mobile robot, AMR, with manipulator for environment perception during navigation and for job detection and identification required for material handling in a manufacturing environment.

Digital controller for attitude control of a rotary-winged flying robot in hover

This paper presents the design of digital controller for attitude control of a rotary-winged flying robot in hover. It describes the best digital implementation of continuous compensation from linear SISO controller to control the nonlinear dynamics of the aerial robot. Results with limits are given for attitude correction against reference attitudes, set for maintaining the hover. Experiments are carried out on Bergen Turbine Observer model, equipped with a NAV420CA INS and mounted on a test rig with bending flexibility in all axes.

IPMC based micro gripper for miniature part handling

This paper presents the behavior of two finger based micro gripper which is made of Ionic Polymer Metal Composite (IPMC), an Electro Active Polymer. IPMC shows great potential as high-displacement and light weight actuator. Low mass force generation capability is utilized for micro gripping in micro assembly. IPMC responds to low voltage in the range of 0–3V. The material contains an electrolyte which transport ions in response to an external electric field. IPMC actuation for micro gripping is produced by deflecting material according to bending moment theory. An external electric field generated by suitable RC circuit causes this deflection. It is found that an IPMC actuates from 1–5 seconds. The maximum jaw opening and closing position of micro gripper are found to be 5 mm and 0.5 mm respectively.

Robust feedback control for attitude stabilization of a Rotary-Winged Flying Robot in hover

This paper addresses attitude stabilization of a Rotary-Winged Flying Robot (RWFR) in hover.1 2 The main objective is to control the dynamic behavior of RWFR. As the physical nature of RWFR is complex in shape and motion, the simple intuitive mathematical modeling fails as the non-linear aerodynamic forces and gravity acts in a non-intuitive manner. Due to limited accuracy of dynamic model, the RWFR attitude dynamics is conditionally stable where a minimum amount of attitude feedback is required for system stability. For attitude compensation with accelerated response, AVCS gyro feedback is necessary to attain a high attitude control bandwidth in response to an attitude reference input. This paper presents RWFR system architecture, provides a detailed analysis of the performance of the controller through closed loop identification and discusses experimental results carried out on Hirobo Scheadu50 model strapped to a test rig with bending flexibility in lateral and longitudinal axes.

Attitude Controller for Steady Hover of a Rotary-Wing Flying Robot

This paper presents an attitude controller for steady hover of CMERI’s Rotary-Wing Flying Robot. The main objective is to control the dynamic behaviour of the robot, which is complex in shape and motion as nonlinear aerodynamic forces and gravity acts on the system. Due to limited accuracy of the dynamic model, the attitude dynamics is conditionally stable where a minimum amount of attitude feedback is required for system stability. To compensate for conditional stability with improved disturbance rejection, an attitude controller is developed adopting cascade control loop architecture. The INS system feedback is used for outer control loop while the gyro feedback is adopted for the inner control loop to attain a high bandwidth, ensuring attitude stability with accelerated response required for a steady hover. The defined controller has introduced corrective control to mitigate the disturbance as sensed by the gyros before they actually do affect the output as the cascade control loop is more responsive than simply the INS loop feedback. In the proposed approach, the robot is modelled using well known “NASA Minimum Complexity Math Model” where robot dynamics is decoupled into Single Input Single Output system. Kalman filter is used to estimate the attitude from the high frequency based gyros aided by INS system feedback data while a matched pole-zero method is used to perform discretization. The stability of the system is evaluated using closed loop identification. The provided solution is tested on Hirobo Scheadu50 model and the system performance is analyzed using the proposed controller.

Rotary-Wing Flying Robot Attitude Controller for Hovering

This paper addresses the control of dynamic behavior of the rotary wing flying robot in hover, which is complex in shape and motion as nonlinear aerodynamic forces and gravity acts on the system. Due to limited accuracy of the dynamic model, the attitude dynamics is conditionally stable where a minimum amount of attitude feedback is required for system stability. To compensate for conditional stability, a controller for both roll and pitch dynamics is developed adopting cascade control loop feedback architecture where INS system feedback is used for outer control loop while the gyro feedback is adopted for the inner control loop to attain a high bandwidth, ensuring attitude stability with accelerated response required for a steady hover. The provided solution is tested on Hirobo Scheadu50 model and the system performance is analyzed during hover using the proposed controller. Through taut integration of simulation and flight-test validation, a controller is developed that is sufficiently accurate, quite effective and simple enough for handling complex and changing rotorcraft dynamics in hover.

Rotary-wing aerial robot configuration for in-flight switching for hovering

This paper describes the configuration of Rotary Wing Aerial Robot developed at CSIR-CMERI for smooth switching while in flight from teleoperated mode to auto mode for steady hovering. This include reading incoming PWM signals from transceiver using high-speed digital FPGA card mounted on the control computer to allow for high-speed data throughput required for switching and ensuring attitude stability with accelerated response required for a steady hover. An indigenous protocol is developed for powerful long distance communication between ground station and RWAR for command, reply and data transmission from a high performance MEMS based miniature Attitude Heading Reference System (AHRS) with GPS. The provided configuration is tested on Hirobo Scheadu50 model.

Studies on effect of basic manuvering operations on quadcopters thrust generated

Miniature robots especially miniature flying robots or vehicles are very fast gaining popularity among researchers. They are versatile in design, very compact and lightweight to carry a few grams of camera or any other payload to do the assigned task or inspection routine in given time frame and can come back to the base station. Miniature robots can be of help in many disaster mitigation, search and rescue operations because of their ability to fly in bad weather conditions as well as difficult to access passages without risking human lives. When flying in such conditions, it is essential to have a air vehicle that can easily fit through small openings and maneuver around pillars and destructed wall structure. To complete the given tasks effectively and in given time is the biggest challenge in designing any such vehicles. In this paper our approach is mainly to design the MAV which will maneuver without any disturbance created by the atmosphere. In brief, a kinematic model of the arrangement of MAV is studied keeping in view different aspects like thrust forces, lift co-efficient, basic maneuvering operations, etc. Another aim is to analyze the deflection in structure of MAV in certain loading conditions.

Studies on effect of pitch and roll variations on quadrotors's thrust generated

In the recent past, Micro Aerial Vehicles (MAV) have gained a lot of interest among researchers due to the innovations in low-power processors and miniature sensors which in turn opened new horizons in terms of miniaturization and its field of application. MAVs are capable of flying in complex or cluttered environments that make office buildings and commercial centers among many other areas possible for aerial surveillance. MAV can also serve in search-and-rescue missions after earthquakes, explosions, etc. An aerial robot capable of flying through narrow spaces and collapsed buildings could quickly and systematically search victims of accidents or natural disasters without risking human lives. When flying in such conditions, it is essential to have a vehicle that can easily fit through small openings and maneuver around pillars and destructed wall structure. To complete the given tasks effectively and in given time is the biggest challenge in designing any such vehicles. In this paper our approach is mainly to design the MAV which will give desired thrust with given set of rotating blade mechanism. In brief, a kinematic model of the arrangement of MAV is studied keeping in view different aspects like thrust forces, lift coefficient, basic maneuvering operations, etc. Ultimate aim is to generate sufficient thrust to effectively maneuver the MAV.