Nonholonomic camera-space manipulation

Abstract

The paper extends to wheeled systems the method of camera-space manipulation. A minimum of two cameras is required to place points on end-effectors (or objects in their grasp) of n-degree-of-freedom manipulators relative to other bodies where the nonholonomic degrees of freedom on a mobile manipulator base may be included. The target bodies do not have a precisely known location relative to the environment. This is accomplished using a sequential estimation scheme that permits placement of these points in each of the two-dimensional image planes of monitoring cameras, resulting in a precise and robust manipulation strategy that is compatible with "real time." The method is illustrated experimentally, though not in real time, using a point placement task. It is then generalized to rigid-body positioning tasks. Although the experimental point placement illustrations make use of a very simple trajectory planning scheme for the wheels of the base, a smoother optimal trajectory planning scheme that makes use of the Pontryagin maximum principle is also developed and illustrated. In a departure from the normal practice of using time as the independent variable for estimation and optimal trajectory planning algorithms, the present development is time independent and instead introduces the forward rotation of the drive wheel of the base as the independent variable.

Automatic visual guidance of a forklift engaging a pallet

“…A form of standard CSM called 'non-holonomic CSM' has been used to control a small mobile manipulator, a 'simulated forklift', that is capable of engaging a small pallet [8,9]. MCSM was developed, in part, to overcome some of the restrictions and disadvantages of using this form of CSM to control mobile manipulators.…”

“…Standard CSM has even been used to control a mobile manipulator, a miniature 'simulated' forklift [8,9]. However, standard CSM is ill-suited to control mobile manipulators since it is limited by the need to control the mobile system using stationary cameras, which severely limits the workspace of the mobile system.…”

Intelligent systems:

“…This generates the need in hybrid control strategy especially for providing feedback stabilization [467, 468,474,475]. The number of controls is smaller than the dimension of the configuration space [469,470].…”

“…Meystel [710]. Nonholonomic camera-space a manipulation is addressed in [720]. A technique of nonholonomic planning for a vehicle moving among obstacles is presented in [721].…”

Object Recognition for Obstacles-free Trajectories Applied to Navigation Control

“…In the job of Nasisi & Carelli, a set of equations needed to establish relationships among a bidimensional image captured by a video camera and its corresponding tri-dimensional image is obtained, an equation set that is important when a single camera is being used. The jobs of S. Skaar et al, (who participated in the 2003 Mars Exploration Rover experiment of NASA), over the concept of Camera Space Manipulation (CSM) (Skaar et al, 1992) and the concept of Mobile Camera Space Manipulation (MCSM) (Seelinger et al, 2002), must be cited. The MCSM method consists of the estimation of the relationship among the characteristics position of the manipulator and its corresponding points in the image spaces of the two cameras mounted over the robot; the CSM concept is quite similar but with more restrictions.…”