Abstract: A controller commands a jack drive to extend and retract a jack leg relative to a jack base along a stroke having retraction and extension limits. The controller updates a perceived present leg position value in response to position change signals from a position change sensor. The controller occasionally applies compensation factors to the perceived present leg position value in the extension direction. The controller resets the perceived present leg position value whenever the jack leg reaches the retraction limit.

Abstract: An electric actuator motor drives an actuator leg between inner and outer limits of an actuator stroke relative to an actuator base. A controller detects when the actuator leg is at one of the inner and outer stroke limits by monitoring and comparing actuator motor power draw to known actuator motor power draw values associated with the operation of an electric actuator when its leg has reached an actuator leg stroke limit. A position sensor senses changes in the position of a monitored actuator component and provides corresponding signals to the controller. The controller calculates the position of the monitored actuator component relative to the position that the monitored actuator component was in when the actuator leg was in a predetermined home position. The controller recognizes and records the concurrent position of the monitored actuator component as indicating that the actuator leg is in the home position whenever the leg reaches a stroke limit.

Abstract: A method and apparatus for increasing platform attitude adjustment range for platforms supported by jacks in which the apparatus includes jacks for supporting a platform at spaced-apart locations, jack drive mechanisms, and a controller connected to each of the jacks through their respective jack drive mechanisms and programmed to adjust platform attitude by coordinating jack movement. The controller coordinates jack movement by selecting and commanding at least one of the jacks to retract and selecting and commanding at least one other of the jacks to extend.

Abstract: An electric actuator motor drives an actuator leg between inner and outer limits of an actuator stroke relative to an actuator base. A controller detects when the actuator leg is at one of the inner and outer stroke limits by monitoring and comparing actuator motor power draw to known actuator motor power draw values associated with the operation of an electric actuator when its leg has reached an actuator leg stroke limit. A position sensor senses changes in the position of a monitored actuator component and provides corresponding signals to the controller. The controller calculates the position of the monitored actuator component relative to the position that the monitored actuator component was in when the actuator leg was in a predetermined home position. The controller recognizes and records the concurrent position of the monitored actuator component as indicating that the actuator leg is in the home position whenever the leg reaches a stroke limit.

Abstract: A controller commands a jack drive to extend and retract a jack leg relative to a jack base along a stroke having retraction and extension limits. The controller updates a perceived present leg position value in response to position change signals from a position change sensor. The controller occasionally applies compensation factors to the perceived present leg position value in the extension direction. The controller resets the perceived present leg position value whenever the jack leg reaches the retraction limit.

Abstract: An electric jack load balancing method and device for reducing the difference in load carried by each jack of a pair of electric jacks while adjusting the attitude of a platform. The device includes a controller configured to reduce the difference in load carried by each jack of a pair of electric jacks. The method includes monitoring the power draws of the jack motors of the pair of electric jacks, comparing the ratio of the power draws of the jack motors to a predetermined desirable power draw ratio, and when the jack motor power draw ratio differs from the desirable power draw ratio, modifying the operation of the jacks in such a way as to decrease the difference between their actual power draw ratio and the predetermined desirable power draw ratio.

Abstract: A method and device for detecting the stroke limit of an electric motor-driven jack while the jack is being used to adjust the attitude of a mobile platform. A controller is programmed to detect when an electric jack motor has driven a jack to a jack stroke limit by monitoring one or more jack motor power draw characteristics and comparing those values to known values associated with the driving of a jack at or near the end of a jack stroke.

Abstract: An electric jack ground contact detection method and device for detecting ground contact of an electric motor-driven jack as the jack is being extended to adjust the attitude of a mobile platform. The device includes a controller that monitors the electrical power draw of an electric motor-driven jack while the jack is being extended for use in adjusting the attitude of a mobile platform. The controller recognizes jack ground contact when the monitored power draw value exceeds a ground contact power draw value consistent with jack ground contact. The controller calculates the ground contact power draw value as equaling the sum of a dynamically-adjusted threshold power draw value associated with jack extension before ground contact and a power draw increase value equaling an amount of additional power that the jack is known to draw as a result of jack ground contact.