In a method of operating a payload-carrying vehicle having a system configured to provide torque to ground contacting elements, the method includes, repeatedly measuring a force applied by a user to the vehicle; determining a direction and a magnitude of the measured force; determining a respective amount of torque to apply to each of the ground contacting elements as a function of the determined direction and magnitude; and providing the respective determined amount of torque to each of the ground contacting elements.

A walk power mower having a cutting deck supported upon the ground by a front and rear wheel(s). The mower includes a traction drive system incorporating a bidirectional transmission adapted to propel the mower alternatively in both forward and reverse directions. In some embodiments, the mower may include a single bidirectional transmission (e.g., powering only rear wheel(s) or only front wheel(s) of the mower), while in other embodiments, two bidirectional transmissions may be provided to power both the front and the rear wheel(s). In other embodiments, the mower may include a bidirectional transmission powering the rear wheel(s), while the front wheel(s) may be attached to the deck via a caster assembly.

A gyroscopically-responsive power assisted moment arm is disclosed for use in connection with vehicles such as load carrying devices. A moment arm extends to a pivot point such that when a longitudinal force is applied at the moment arm, a sensor senses such force and outputs an energizing signal to a motor to drive a wheel. If a rotational or vertical force is applied to the moment arm, the motor need not be driven. According to the invention, therefore, a power assist can be provided to a user to drive a wheel in a desired direction of transport while not causing drive during tipping or unloading of the load carrying portion of the vehicle. Such an apparatus can be advantageously applied to a power assisted wheelbarrow, as one exemplary application.

A walk power mower having a cutting deck supported upon the ground by a front and rear wheel(s). The mower includes a traction drive system incorporating a bidirectional transmission adapted to propel the mower alternatively in both forward and reverse directions. In some embodiments, the mower may include a single bidirectional transmission (e.g., powering only rear wheel(s) or only front wheel(s) of the mower), while in other embodiments, two bidirectional transmissions may be provided to power both the front and the rear wheel(s). In other embodiments, the mower may include a bidirectional transmission powering the rear wheel(s), while the front wheel(s) may be attached to the deck via a caster assembly.

A power assist device may include a motor, a motor driving circuit, sensors to output signals in accordance with a rotational speed of the wheel, a memory, and a signal processor. The memory stores information of a parameter defining a transfer function that interrelates a total torque to be input to the vehicle and a rotational speed of the wheel, and an inverse transfer function thereof. Based on the inverse transfer function, the signal processor determines an estimated value of total torque from a detected value of rotational speed of the wheel. Moreover, based on the transfer function, the signal processor updates at least a portion of the information of the parameter so that, for example, an error between a detected value of rotational speed of the wheel and an estimated value of rotational speed of the wheel as determined from the estimated value of total torque is reduced.

A mobile X-ray imaging apparatus has an angle sensor and a movement calculation circuit that controls the driving of drive wheels based on the turning angle of auxiliary wheels relative to a straight moving direction of the base unit when a fine movement switch instructs movement of the base unit in the fine movement mode. The turning angle of auxiliary wheels is detected by a turning angle sensor and the rotation of the pair of drive wheels is controlled by the movement calculation circuit as the auxiliary wheels turns to the straight moving direction.

A carriage has a carriage body having a loading platform for bearing a load and a plurality of wheels rotatably retained to the loading platform, an operation handle connected to the carriage body and grasped by a user operating the carriage, a sensor for measuring information related to a force applied to the operation handle, and a driving device for outputting a driving force based on a result of detection by the sensor to any of the plurality of wheels.

A carriage is used to convey a load. The carriage has a carriage body having a frame and a plurality of wheels rotatably retained to the frame, a loading platform supported to the carriage body and bearing the load, a sensor for detecting a relative movement between the carriage body and the loading platform, and a driving device for outputting a driving force based on a result of detection by the sensor to any of the plurality of wheels.

An electric push cart includes a motor; a drive wheel that is rotationally driven by the motor; a cart frame that rotatably supports the drive wheel and includes left and right handles for a user to hold; a controller that drives the motor and issues a warning. The controller issues a warning when a motor-stop condition is fulfilled as a result of an increase in load on the motor when driving the motor and stops the drive of the motor after a given time has elapsed.

A power assist system for a wagon having a safety cut-off system is provided. The power assist system preferably includes a wagon body having a plurality of wheels, at least one of which is a driven wheel, a pivotable handle, a drive system having a motor mechanically connected to the driven wheel, a microcontroller that obtains an input signal and provides an output signal to the drive system and, a safety cut-off system connected to the handle. In one embodiment the safety cut-off system includes a safety-control switch electrically connected to the microcontroller, and the microcontroller adjusts the signal sent to the drive system based on a state of the safety-control switch.