An anti-roll stabilizer device for boats includes a container adapted to be mounted on a suspension so as to oscillate around a first axis; a mass rotatably supported inside the container so as to form a rotor that rotates around a second axis transverse to the first axis; and a rotor cooling system having a hollow shaft arranged along the second axis, a first and a second cooling chamber sealed from the container of the rotor and from the outside, arranged at the ends of the hollow shaft and communicating through the hollow shaft, the first chamber having an inlet and the second chamber an outlet that are connected to a forced circulation circuit of the cooling fluid so that the cooling fluid can circulate from the first chamber to the second chamber through the hollow shaft and from the second chamber to the first chamber through the circulation circuit.

Embodiments provided herein measure metrics of an athletic action and an object associated therewith, and more particularly, to measuring the metrics and characteristics of a baseball during the wind-up, release, flight, and catch of a pitch sequence. Methods may include: receiving, from at least one motion sensor associated with an object, acceleration data and angular velocity data of the object in response to an athletic action performed on the object; processing the acceleration data to establish vector rotation data between a frame of reference of the object and an Earth frame of reference; applying the vector rotation data to the acceleration data to obtain acceleration of the object in the Earth frame of reference; applying the vector rotation data to the angular velocity data to obtain angular velocity of the object in the Earth frame of reference.

Embodiments provided herein measure metrics of an athletic action and an object associated therewith, and more particularly, to measuring the metrics and characteristics of a baseball during the wind-up, release, flight, and catch of a pitch sequence. Methods may include: receiving, from at least one motion sensor associated with an object, acceleration data and angular velocity data of the object in response to an athletic action performed on the object; processing the acceleration data to establish vector rotation data between a frame of reference of the object and an Earth frame of reference; applying the vector rotation data to the acceleration data to obtain acceleration of the object in the Earth frame of reference; applying the vector rotation data to the angular velocity data to obtain angular velocity of the object in the Earth frame of reference.

A travelling direction calculation apparatus includes an acceleration sensor, a period identification unit, an action determination unit, a vector calculator, and a travelling direction decision unit. The period identification unit identifies a stable measurement period and an idling leg period based on change in a vertical component of acceleration detected by the acceleration sensor. The action determination unit discriminates between walking and running by using the minimum value of the vertical component of the acceleration in the idling leg period. The vector calculator calculates a velocity vector from a horizontal component of the acceleration in the stable measurement period. The travelling direction decision unit decides a direction of traveling of a user based on a result of determination performed by the action determination unit and the velocity vector calculated by the vector calculator.

A travelling direction calculation apparatus includes an acceleration sensor, a period identification unit, an action determination unit, a vector calculator, and a travelling direction decision unit. The period identification unit identifies a stable measurement period and an idling leg period based on change in a vertical component of acceleration detected by the acceleration sensor. The action determination unit discriminates between walking and running by using the minimum value of the vertical component of the acceleration in the idling leg period. The vector calculator calculates a velocity vector from a horizontal component of the acceleration in the stable measurement period. The travelling direction decision unit decides a direction of traveling of a user based on a result of determination performed by the action determination unit and the velocity vector calculated by the vector calculator.

Product transport structures are provided which include a self-stabilizing platform assembly configured to support a product on a deck of the self-stabilizing platform assembly and to stabilize the product during moving of the self-stabilizing platform assembly and product. The self-stabilizing platform assembly includes multiple torque-generating devices and a stability control system. The multiple torque-generating devices are controllable to produce a stabilization torque within the self-stabilizing platform assembly, and the stability control system is configured to control operation of the multiple torque-generating devices. The stability control system is configured to adjust operation of one or more torque-generating devices of the multiple devices to produce the stabilization torque to facilitate stabilizing the product during moving of the self-stabilizing platform assembly and product.

Product transport structures are provided which include a self-stabilizing platform assembly configured to support a product on a deck of the self-stabilizing platform assembly and to stabilize the product during moving of the self-stabilizing platform assembly and product. The self-stabilizing platform assembly includes multiple torque-generating devices and a stability control system. The multiple torque-generating devices are controllable to produce a stabilization torque within the self-stabilizing platform assembly, and the stability control system is configured to control operation of the multiple torque-generating devices. The stability control system is configured to adjust operation of one or more torque-generating devices of the multiple devices to produce the stabilization torque to facilitate stabilizing the product during moving of the self-stabilizing platform assembly and product.

When calculating a gimbal angle trajectory that satisfies boundary conditions set by an attitude boundary condition setter 2131 of the ground station 21, a gimbal angle trajectory calculator 2132 calculates the gimbal angle trajectory that minimizes a period of an acceleration interval within a range that satisfies driving restrictions of a gimbal, based on a gimbal angle θ.sub.0i of a start time and a gimbal angle θ.sub.ci of a fixed interval of an attitude change. Also, the gimbal angle trajectory is calculated that minimizes a period of a deceleration interval within a range that satisfies the driving restrictions of the gimbal, based on the gimbal angle θ.sub.ci of the fixed interval and a gimbal angle θ.sub.fi of a completion time of the attitude change. The obtained θ.sub.0i, θ.sub.ci, θ.sub.fi and an attitude change period τ are transmitted to the artificial satellite as gimbal angle trajectory parameters, and the control moment gyros are controlled based on the gimbal angle trajectory parameters.

When calculating a gimbal angle trajectory that satisfies boundary conditions set by an attitude boundary condition setter 2131 of the ground station 21, a gimbal angle trajectory calculator 2132 calculates the gimbal angle trajectory that minimizes a period of an acceleration interval within a range that satisfies driving restrictions of a gimbal, based on a gimbal angle θ.sub.0i of a start time and a gimbal angle θ.sub.ci of a fixed interval of an attitude change. Also, the gimbal angle trajectory is calculated that minimizes a period of a deceleration interval within a range that satisfies the driving restrictions of the gimbal, based on the gimbal angle θ.sub.ci of the fixed interval and a gimbal angle θ.sub.fi of a completion time of the attitude change. The obtained θ.sub.0i, θ.sub.ci, θ.sub.fi and an attitude change period τ are transmitted to the artificial satellite as gimbal angle trajectory parameters, and the control moment gyros are controlled based on the gimbal angle trajectory parameters.

Various implementations include a personal sonar system sized to be worn on a body of a user. In some cases, the system includes: at least one acoustic transmitter for transmitting ultrasonic signals into an environment proximate the user; at least two acoustic receivers for receiving return ultrasonic signals from the environment proximate the user; a directional indication system for providing a directional output to the user; and a controller coupled with the at least one transmitter, the at least two acoustic receivers, and the directional indication system, the controller configured to: identify a physical object within the environment proximate the user based on the return ultrasonic signals; and initiate the directional output at the directional indication system based on the identified physical object within the environment.