This paper presents a differential-flatness-based integrated point-to-point trajectory planning and control method for a class of nonholonomic wheeled mobile manipulator (WMM). We demonstrate that its kinematic model possesses a feedback-linearizable description due to the flatness property, which allows for full-state controllability. Trajectory planning can then be simplified and achieved by polynomial fitting method in the flat output space to satisfy the terminal conditions, while control design reduces to a pole-placement problem for a linear system. The method is then deployed on our custom-constructed WMM hardware to evaluate its effectiveness and to highlight various aspects of the hardware implementation.

Power mobility is a critical assistive technology for many children with special needs. Our previous work suggests that certain infants younger than the age 1 year of age can participate in formal power mobility training. This case report describes the feasibility of providing a power mobility training program with a young infant with spina bifida. Specifically, we longitudinally quantified the infant's driving ability with a joystick-controlled device (UD1), using UD1's onboard computer and video camera from an infant's age of 7 to 12 months. During the training period, the infant improved in all driving variables. The infant's Bayley III cognition and language scores also increased at a rate greater than his chronological age. These results suggest that power mobility training within the first year of life may be appropriate for certain populations at risk of immobility.

This paper presents feedback stabilization control of a rolling manipulation system called the disk-on-disk. The system consists of two disks in which the upper disk (object) is free to roll on the lower disk (hand) under the influence of gravity. The goal is to stabilize the object at the unstable upright position directly above the hand. We show that it is possible to stabilize the object at the upright position, while the hand or object rotates to a specific orientation or spins at a constant velocity. We use full-state feedback linearization to derive control laws. We present simulation as well as experimental results demonstrating the controllers.