Abstract
Japanese Orchard workers have to spend time for hand labor such as flower thinning, fruit thinning, leaves thinning, harvesting and pruning. Additionally, most growers use a stepladder for working around the upper part of trees. To reduce these labors, and to help workers work safely, we developed a mobile elevating work platform which has high mobility and is easily operable. The device consists of a horizontal stability control device, and an omnidirectional steering system. The horizontal stability control device has two axes that can be independently driven. The control system uses two sensor's signals, an acceleration sensor and a gyro sensor, and calculates the angle and the angular velocity via steady-state Kalman filter. These states are fed back to motor torque to control the device angle. The omnidirectional moving platform has four wheel driving units that can independently control the steering angles and the rotation speeds. This enables the vehicle to move by steering of normal, crab, spin and other various modes. Workers can operate the vehicle with only one joystick. When the joystick is tilted the vehicle moves to the corresponding direction. When the joystick is twisted, the vehicle turns to the corresponding direction.
