A hyper-redundant manipulator

“Hyper-redundant” manipulators have a very large number of actuatable degrees of freedom. The benefits of hyper-redundant robots include the ability to avoid obstacles, increased robustness with respect to mechanical failure, and the ability to perform new forms of robot locomotion and grasping. The authors examine hyper-redundant manipulator design criteria and the physical implementation of one particular design: a variable geometry truss

A "Sidewinding" Locomotion Gait for Hyper-Redundant Robots

This paper considers the kinematics of a novel form of hyper-redundant mobile robot locomotion which is analogous to the 'sidewinding' locomotion of desert snakes. This form of locomotion can be generated by a repetitive travel wave of mechanism bending. Using a continuous backbone curve model, we develop algorithms which enable travel in a uniform direction as well as changes in direction

Design and MIMO control of A Hyper-Redundant Robotic Arm

An application robotic platform has been constructed based on the kinematic model of a 9-DOF hyper-redundant manipulator. The efficacy of our kinematic algorithm affects the accuracy and stability of both motion control and path tracking. An objective of this work is to achieve multi-input multi output (MIMO) control, where the inputs are the torques at each joint, and they are used to control joint dynamic variables such as position, orientation, velocity and acceleration in a hyper-redundant robotic system. This control approach can highly improve the robotic performance considering both its kinematics and dynamics while executing motion control or tracking a path. The result of tracking different paths and the error analysis both in joint space and work space show that the MIMO control algorithm works functionally and satisfies all the requirements of experimental design.https://ecommons.udayton.edu/stander_posters/1642/thumbnail.jp

Mobile-manipulating UAVs for Sensor Installation, Bridge Inspection and Maintenance

Mobile manipulating UAVs have great potential for bridge inspection and maintenance. Since 2002, the PI has developed UAVs that could fly through in-and-around buildings and tunnels. Collision avoidance in such cluttered near-Earth environments has been a key challenge. The advent of light-weight, computationally powerful cameras led to breakthroughs in SLAM even though SLAM-based autonomous aerial navigation around bridges remains an unsolved problem. In 2007, the PI integrated a mobile manipulation function into UAVs, greatly extending the capabilities of UAVs from passive survey of environments with cameras to active interaction with environments using limbs. Mobile-manipulating UAVs have since been demonstrated to successfully turn valves, install sensors, open doors, and drag ropes. Their research and development face several challenges. First, limbs add weight to aircraft. Second, rotorcraft, like a quadcopter, is an under-actuated system whose stability can be easily affected by limb motions. Third, when performing a task like turning a valve, limbs demand compensation for torque-force interactions. Thus, even if battery technologies afford the additional payload of limbs, current knowledge for manipulation with under-actuated systems remains sparse. This project aims to develop and prototype a mobile-manipulating UAV for bridge maintenance and disaster cleanup through further study on SLAM technology for robust navigation, impedance controllers to ensure UAV’s stability with limb motion, and coordinated and cooperative motions of multiple limbs to perform simple tasks like bearings cleaning and crack sealing in concrete bridges. Two strategies will be explored for bridge maintenance: (a) A UAV brings and uses a can of compressed air for bridge cleaning, and (2) Two UAVs airlift, position, and operate hoses from ground, and clean bridges with air or water. The latter can be potentially implemented by including a station-keeping, lighter-than-air UAV like blimp that can airlift a hose and remain airborne for extended periods. The mobile-limbed UAVs can then pull-and-drag the hose into areas that need to be cleaned. The blimp-based approach is attractive because it is easier for a UAV to drop hose lengths rather than pull the hose up in air

Instantaneous inverse kinematic solution for redundant manipulators based on virtual arms and its application to winding control

The present paper proposes an instantaneous inverse kinematic solution for redundant manipulators based on virtual arms. The virtual arm has the same kinematic structure as the manipulator except that its end-point is located on the joint or link of the manipulator. When the appropriate virtual arms are used, the configuration of the manipulator can be represented by a set of end-points of the virtual arms. First of all, this paper formalizes the kinematics of virtual arms and derives instantaneous inverse kinematics. Then, the method is applied to winding control for hyper-redundant manipulators. The winding control presented here is divided into two steps: 1)planning desired positions for virtual end-points, 2)integrating them into the joint trajectory of the manipulator. The desired positions of each virtual arm can be computed in a parallel and distributed way and it is not necessary to consider joint space of the manipulator. Finally computer simulations show that the winding control for a hyper-redundant manipulator can be performed in 3D-space

Lightweight robotic arm actuated by Shape Memory Alloy (SMA) Wires

The current paper discusses the design, modeling and control of a Light weight robotic arm actuated by Shape Memory Alloy (SMA) actuators, usable for applications such as Aerial Manipulator. Compared to servo motor based robotic arm the proposed design has an added advantage of light weight and high force to mass ratio, but further introduces the problem of nonlinearities such as Hysteresis into the system. A nonlinear dynamic model of the hysteretic robotic arm is systematically developed to perform closed loop simulations. A Joint Space control is performed using Variable Structure Control and the closed loop performance is successfully verified by simulation studies