The invention relates to a drive arrangement for a vehicle and a method for gear shifting in a vehicle. The drive arrangement (5) comprises at least a first drive axle (10, 20, 30) operatively connected to a first gear box (11) and a first propulsion unit (12). The drive arrangement (5) further comprises a second gear box (21) and a second propulsion unit (22) operatively connected to the first drive axle (10) or to an optional second drive axle (20, 30). The drive arrangement (5) further comprises at least one electronic control unit (ECU) adapted to govern gear transmission of the first and the second gear boxes (11, 21). The electronic control unit (ECU) is configured to automatically select between shifting gear on the first and the second gear boxes (11, 21) simultaneously, or sequentially. The drive arrangement and the method provides for a very versatile drive arrangement and gear synchronization providing comfort for the driver and the passengers as well as improved vehicle dynamics.

The invention relates to a drive arrangement for a vehicle and a method for gear shifting in a vehicle. The drive arrangement (5) comprises at least a first drive axle (10, 20, 30) operatively connected to a first gear box (11) and a first propulsion unit (12). The drive arrangement (5) further comprises a second gear box (21) and a second propulsion unit (22) operatively connected to the first drive axle (10) or to an optional second drive axle (20, 30). The drive arrangement (5) further comprises at least one electronic control unit (ECU) adapted to govern gear transmission of the first and the second gear boxes (11, 21). The electronic control unit (ECU) is configured to automatically select between shifting gear on the first and the second gear boxes (11, 21) simultaneously, or sequentially. The drive arrangement and the method provides for a very versatile drive arrangement and gear synchronization providing comfort for the driver and the passengers as well as improved vehicle dynamics.

A power extraction system is provided and includes a low-pressure spool of a gas turbine engine, the low-pressure spool being rotatable at an input rotational speed between a first minimum speed and a first maximum speed, downstream components rotatable at an output rotational speed between a second minimum speed and a second maximum speed and a transmission assembly by which rotations of the low-pressure spool at the input rotational speed are transmittable at the output rotational speed to the downstream components. The transmission assembly includes clutches and a controller configured to control openings and closings of the clutches according to an upshifting algorithm whereby a torque applied by the downstream components is used to reduce the output rotational speed to an output speed of a gear into which the transmission assembly is shifting.

A power extraction system is provided and includes a low-pressure spool of a gas turbine engine, the low-pressure spool being rotatable at an input rotational speed between a first minimum speed and a first maximum speed, downstream components rotatable at an output rotational speed between a second minimum speed and a second maximum speed and a transmission assembly by which rotations of the low-pressure spool at the input rotational speed are transmittable at the output rotational speed to the downstream components. The transmission assembly includes clutches and a controller configured to control openings and closings of the clutches according to an upshifting algorithm whereby a torque applied by the downstream components is used to reduce the output rotational speed to an output speed of a gear into which the transmission assembly is shifting.

Disclosed is a compound harmonic gear motor having: first and second ground gears connected by a stationary shaft; a wave generator including an outer surface that can rotate completely around the stationary shaft, the wave generator including a rotor and a stator, wherein rotation of the rotor causes rotation of the outer surface; a flex spline surrounding the outer surface of the wave generator that is driven to rotate by rotation of the outer surface of the wave generator; and an output flange including internal teeth that mate with the flex spline to cause rotation of the output flange completely around the stationary shaft.

Disclosed is a compound harmonic gear motor having: first and second ground gears connected by a stationary shaft; a wave generator including an outer surface that can rotate completely around the stationary shaft, the wave generator including a rotor and a stator, wherein rotation of the rotor causes rotation of the outer surface; a flex spline surrounding the outer surface of the wave generator that is driven to rotate by rotation of the outer surface of the wave generator; and an output flange including internal teeth that mate with the flex spline to cause rotation of the output flange completely around the stationary shaft.

A power extraction system is provided and includes a low-pressure spool of a gas turbine engine, the low-pressure spool being rotatable at an input rotational speed between a first minimum speed and a first maximum speed, downstream components rotatable at an output rotational speed between a second minimum speed and a second maximum speed and a transmission assembly by which rotations of the low-pressure spool at the input rotational speed are transmittable at the output rotational speed to the downstream components. The transmission assembly includes clutches and a controller configured to control openings and closings of the clutches according to an upshifting algorithm whereby a torque applied by the downstream components is used to reduce the output rotational speed to an output speed of a gear into which the transmission assembly is shifting.

A power extraction system is provided and includes a low-pressure spool of a gas turbine engine, the low-pressure spool being rotatable at an input rotational speed between a first minimum speed and a first maximum speed, downstream components rotatable at an output rotational speed between a second minimum speed and a second maximum speed and a transmission assembly by which rotations of the low-pressure spool at the input rotational speed are transmittable at the output rotational speed to the downstream components. The transmission assembly includes clutches and a controller configured to control openings and closings of the clutches according to an upshifting algorithm whereby a torque applied by the downstream components is used to reduce the output rotational speed to an output speed of a gear into which the transmission assembly is shifting.

A linkage mechanism including a base, a first linkage, a second linkage and a driving element is provided. The first linkage has a first end portion and a second end portion opposite to each other, and the first end portion is pivoted to the base. The second linkage has third end portion and a fourth end portion opposite to each other, wherein the third end portion is coupled to the base, and the second end portion and the fourth end portion are coupled with each other. The driving element is coupled to at least one of the second end portion and the fourth end portion, and is configured to drive the first linkage and the second linkage to move relative to the base. A walking aid device is also provided.

A linkage mechanism including a base, a first linkage, a second linkage and a driving element is provided. The first linkage has a first end portion and a second end portion opposite to each other, and the first end portion is pivoted to the base. The second linkage has third end portion and a fourth end portion opposite to each other, wherein the third end portion is coupled to the base, and the second end portion and the fourth end portion are coupled with each other. The driving element is coupled to at least one of the second end portion and the fourth end portion, and is configured to drive the first linkage and the second linkage to move relative to the base. A walking aid device is also provided.