Omnidirectional vehicle with passive revolute joints
An omnidirectionally orientable vehicle comprising a main body, arms extending radially therefrom and orientable propulsion modules. Each propulsion module is coupled to an arm and comprises at least three propulsion units rigidly attached to the propulsion module. Each propulsion module is coupled to the arm by interposition of a rotary junction formed by a first revolute joint coupled to the arm and a second revolute joint attached to the propulsion module and perpendicularly coupled to the first revolute joint. The first revolute joint allows the propulsion module to rotate around the arm and the second revolute joint allows the propulsion module to rotate around an axis perpendicular to the arm providing the propulsion module with two DOF relative to the main body. The vehicle comprises rotary encoders located in proximity to the revolute joints and configured to monitor the orientation of the propulsion modules relative to the main body.
1 . An omnidirectional vehicle ( 100 ), comprising:
a main body ( 101 );
a plurality of arms ( 102 a - d ) extending radially from the main body ( 101 ) and coupled thereto; and
a plurality of orientable propulsion modules ( 103 a - d ),
each orientable propulsion module ( 103 a - d ) being coupled to a respective arm ( 102 a - d ) and comprising:
a frame ( 106 ), and
at least three propulsion units ( 105 ) are rigidly attached to the frame ( 106 ) at a respective fixed positions and orientations;
wherein each one of the plurality of orientable propulsion modules ( 103 a - d ) is coupled to the respective arm ( 102 a - d ) by interposition of a rotary junction ( 107 ), the rotary junction being formed by a first passive revolute joint coupled to the arm ( 102 a - d ) and a second passive revolute joint coupled to the orientable propulsion module ( 103 a - d ) wherein a rotation axis of the second revolute joint is perpendicular and coplanar to a rotation axis of the first revolute joint;
wherein the first revolute joint is configured to allow the orientable propulsion module ( 103 a - d ) to rotate around the arm ( 102 a - d ) and the second revolute joint is configured to allow the orientable propulsion module ( 103 a - d ) to rotate around a rotary shaft ( 117 ) which is perpendicular to the arm ( 102 a - d ) such that the orientable propulsion module ( 103 a - d ) is provided with two degrees of freedom with respect to the main body ( 101 ); and
comprising a rotary encoder ( 115 ) located in proximity to each revolute joint that is configured to monitor the orientation of each orientable propulsion module ( 103 a - d ) relative to the main body ( 101 );
wherein each rotary junction ( 107 ) comprises a body having a first orifice 123 ) through which the corresponding arm ( 102 a - d ) is inserted and around which the rotary junction ( 107 ) is to rotate and a second orifice ( 125 ) perpendicular to the first orifice ( 123 ) through which a rotary shaft ( 117 ) coupled to the respective orientable propulsion module ( 103 a - d ) is inserted and inside which the rotary shaft ( 117 ) is to rotate;
and wherein the rotary junction is a single body in which both consecutive and perpendicular revolute joints are integrated.
2 . The omnidirectional vehicle ( 100 ) according to claim 1 , wherein the centres of rotation of the plurality of orientable propulsion modules lay in the geometric axes of the plurality of arms ( 102 a - d ), while being coplanar with a longitudinal axis and a mid-plane of the frame ( 106 ) of the orientable propulsion modules ( 103 a - d ).
3 . The omnidirectional vehicle ( 100 ) according to claim 2 , wherein each one of the at least three propulsion units ( 105 ) is configured to generate a torque and wherein said torque is generated so as to be functionally independent of the thrust modulus generated by said propulsion unit.
4 . The omnidirectional vehicle ( 100 ) according to claim 1 , wherein each one of the at least three propulsion units ( 105 ) is an independently controllable propulsion unit and is configured to generate an independent thrust modulus.
5 . The omnidirectional vehicle ( 100 ) according to claim 1 , wherein the at least one of the at least three propulsion unit ( 105 ) is selected from a group comprising rotors, propellers, turboprop engines, jet engines and any combination thereof.
6 . The omnidirectional vehicle ( 100 ) according to claim 1 , wherein a centre of mass of the orientable propulsion modules ( 103 a - d ) in landing configuration are located below a centre of rotation of their respective rotary junctions ( 107 ).
7 . The omnidirectional vehicle ( 100 ) according to claim 1 , wherein the omnidirectionally orientable vehicle ( 103 a - d ) is selected from a group comprising an omnidirectional aerial vehicle, an omnidirectional underwater vehicle, an omnidirectional space aerial vehicle or any combination thereof.
8 . The omnidirectional vehicle ( 100 ) according to claim 1 , comprising slip rings ( 126 a - c ) electrically connecting the main body ( 101 ) and the orientable propulsion modules ( 103 a - d ), the slip rings ( 126 a - c ) being configured to allow transmission of at least one of data and electrical power between the main body ( 101 ) and the orientable propulsion modules ( 103 a - d ).
9 . The omnidirectional vehicle ( 100 ) according to claim 1 , comprising: a controller and a plurality of loose cables ( 131 ) electrically connecting the main body ( 101 ) and the orientable propulsion modules ( 103 a - d ),
wherein the controller operate the rotary junction according to an automatic unwinding algorithm or a mechanical limit such that a number of loops of the loose cables ( 131 ) is limited and the plurality of loose cables ( 131 ) are configured to allow transmission of at least one of data and electrical power between the main body ( 101 ) and the orientable propulsion modules ( 103 a - d ).
10 . The omnidirectional vehicle ( 200 ) according to claim 1 , comprising a controller ( 202 ) located in the main body ( 201 ) configured to operate the plurality of orientable propulsion modules ( 204 a - d ).
11 . The omnidirectional vehicle ( 300 ) according to claim 1 , comprising:
a primary controller ( 302 ) located in the main body ( 301 ); and
a plurality of secondary controllers ( 305 ), each secondary controller ( 305 ) being located in a corresponding orientable propulsion module ( 304 a - d );
wherein each secondary controller ( 305 ) is configured to operate the respective orientable propulsion module ( 304 a - d ) it is mounted on and the primary controller ( 302 ) is configured to manage the plurality of secondary controllers ( 304 a - d ).
12 . The omnidirectional vehicle ( 100 ) according to claim 1 , wherein the omnidirectional vehicle ( 100 ) is an overactuated omnidirectional vehicle.
13 . A method ( 400 ) for manoeuvring an omnidirectional vehicle, comprising:
providing ( 401 ) an omnidirectional vehicle as claimed in claim 1 comprising, preferably an overactuated omnidirectional vehicle;
determining ( 402 ) a displacement of the main body of the omnidirectional vehicle in cartesian space;
determining ( 403 ), by a controller of the omnidirectional vehicle, a thrust and an orientation for the omnidirectional vehicle based on the determined displacement;
determining ( 404 ), by the controller, the thrust and orientation of each one of the plurality of orientable propulsion modules based on the determined thrust and orientation of the omnidirectional vehicle; and
adjusting ( 405 ), by the controller, a tilt angle of each one the plurality of orientable propulsion modules by performing a rotational movement of each orientable propulsion module relative to the main body via the rotary junctions, the relative rotational movement being based on the determined orientation.