Patent Description:
Connection devices for charging electric vehicles automatically are known in the art. <CIT> discloses a connection device for conductive charging providing lifting means to move a charging head towards a stop surface provided on an underbody of a vehicle. Upon striking the stop surface, continued actuation of the lifting means provides alignment along the stop surface. The disadvantage of such a connection device is that it allows a limited lateral offset and therefore requires very accurate positioning of the vehicle. Furthermore, considerable lifting force will be required for moving the charging head along the stop surface orthogonal to the direction of the lifting force.

<CIT> discloses a more complex connection system for inductive charging allowing more positioning freedom for the vehicle through the use of stacked linear actuators. The system comprises orthogonally placed linear actuators for moving a body comprising a charging coil in the horizontal plane, wherein the body further comprises a pantograph mechanism for moving the charging coil in the vertical direction. The disadvantage of such a connection system is that it requires a large number of moving elements, which are sensitive to fouling and it are difficult to shield.

<CIT> discloses an alternative solution for actively moving a plug in a volume through the use of a number of stacked rotary and linear actuators. The system comprises a rotatable platform provided with a set of stacked linear actuators. The disadvantage of such a manipulator is of such a connection system is that it requires a large number of moving elements, which are sensitive to fouling and it are difficult to shield. Furthermore, it requires the use of an axisymmetric charging head, because the charging head rotates when the rotatable platform is rotated.

It is an object of the invention to provide a manipulator that solves at least one disadvantage and preferably all disadvantages of the prior art.

According to a first aspect of the invention the object is achieved by providing a manipulator according to the appended claims. For instance, a manipulator for positioning an end effector such as an energy transfer unit for charging vehicles. The manipulator comprises a support and a stage comprising the end effector. The manipulator further comprises a first link connecting the stage and the support. The first link may comprise a first end providing a first pivoting connection connected to the support and a second end providing a second pivoting connection connected to the stage. The first link may define a first longitudinal axis between the first end and the second end. Typically, such first link comprises an elongate member extending between the first end and the second end. The manipulator further comprises a first and a second actuating mechanism providing an actuatable connection between the stage and the support through the first link. Each of the first and the second actuating mechanisms may be configured to exert a first (linear) actuating force on the first link for moving the second end of the first link (relative to the support or the first end of the first link) through a volume. The manipulator may further comprise a second link (e.g. an elongate member, such as a cable or a rod) comprising a first end providing a first pivoting connection connected to the support and a second end providing a second pivoting connection connected to the stage at a first position offset from the second pivoting connection of the first link.

The first link and the first and second actuating mechanism provide a means for positioning the end effector (e.g. an energy transfer device) using a limited number of moving parts, thereby improving the robustness and limiting the sensitivity with respect to fouling. Furthermore, by connecting the first and second actuating mechanism to the stage through the first link enables manipulator configurations wherein the first link is the single main body that moves through the environment while positioning the end effector. In addition, the second link provides a means for substantially maintaining an orientation of the end effector along a direction, thereby enabling the use of a non-axisymmetric (conductive or inductive) energy transfer unit and/or reducing the alignment requirements for the vehicle.

In a beneficial embodiment, the first actuating mechanism and the second actuating mechanism jointly define a parallel actuating mechanism configured to exert a first actuating force on the first link for moving the second end of the first link (relative to the support or the first end of the first link) through a volume. A parallel actuating mechanism in this disclosure should be interpreted as a mechanism functionally arranged in parallel as opposed to functionally arranged in series, or in other words stacked, and thus should not be interpreted restrictively as meaning geometrically arranged in parallel.

Beneficially, the first actuating and the second actuating mechanism each comprise a first end (directly) connected to the support, for instance the first and second actuating mechanism are arranged (directly) on the support, and a second end (directly) connected to the first link. The second end of the first actuating mechanism and the second end of the second actuating mechanism may be connected to the first link at a first and second location of the first link, respectively, wherein the first and second location are arranged offset from the first end of the first link. Preferably, the first and second actuating mechanism are configured to adapt a distance between the corresponding first and second end, such that an actuating force is exerted on the first link for moving the second end of the first link (relative to the support or the first end of the first link) through a volume is generated between the first and the second end. Preferably, the first and second actuating mechanism are structurally similar.

Beneficially, a first tension exerted by the first link at the second end of the first actuating mechanism and a second tension exerted by the first link at the second end of the second actuating mechanism each comprise a first directional component, wherein the first directional component of the first and second tension are arranged in a same sense of direction. Beneficially, the first and second tension each comprise a second directional component orthogonal to the first directional component, wherein the second directional component of the first and second tension are arranged in an opposite sense of direction.

Preferably, the first actuating force of the first and second actuating mechanism each provide a torque about the first pivoting connection of the first link. The torques provided by the first and the second actuating mechanism are configured to move the second end of the first link through a volume. For instance, a direction of the torque provided by the first actuating mechanism is not parallel to a direction of the torque provided by the second actuating mechanism. The manipulator may be configured such that a direction of the torque provided by the first actuating mechanism is orthogonal to a directional component of a direction of the torque provided by the second actuating mechanism.

Preferably, the manipulator is configured such that each of the first actuating forces of the first and second actuation mechanism are oblique to the first longitudinal axis. Such first actuation forces may each have a first directional component parallel to the first longitudinal axis. Such first actuation forces may each have a second directional component perpendicular to the first longitudinal axis. Additionally, such first actuation forces may each have a third directional component perpendicular to the corresponding first and second directional component.

In an embodiment of a manipulator according to the present invention, the actuating forces of the first and the second actuating mechanisms may be exerted on the first link at a first and second location of the first link, respectively. Both the first and second location may be provided offset from a longitudinal axis defined by the first link, preferably at opposing sides of the longitudinal axis. The actuation force of the first and second actuating mechanism in such embodiments may be configured to be parallel, but preferably a direction of the actuation force of the first actuation mechanism is configured orthogonal to a directional component of the actuation force of the second actuation mechanism. The first and second location may however also coincide in the event that the actuation force of the first actuation mechanism is configured to be orthogonal to a directional component of the actuation force of the second actuation mechanism.

To allow more freedom with respect to alignment requirements, the end effector may be connected to the stage at a second position offset from the second pivoting connection of the first link (e.g. an axis of rotation of the stage). Preferably, the end effector comprises an energy transfer unit, wherein the energy transfer unit advantageously is pivotally connected to the stage.

The first and second actuating mechanism may comprise any suitable means for providing the corresponding actuating force exerted on the first link. Actuating mechanisms in the present disclosure therefore comprise an active component such as an actuator (e.g. motor). Examples of suitable actuating mechanisms comprise actuating mechanisms comprising a rotary motor and a cable connection, actuating mechanism comprising comprise linear magnetic motors or actuating mechanisms comprising a rotary motor and gears (e.g. rack and pinion, belt drive) configured for providing a linear motion.

Advantageously, the first and second actuating mechanisms comprise a third and a fourth link, respectively. The third and fourth link may comprise a first end providing a first pivoting connection connected to the support and/or a second end providing a second pivoting connection connected to the first link. The first actuating mechanism may comprise a first actuator configured for moving the first end of the third link relative to the support along a first trajectory (e.g. linear) and the second actuating mechanism may comprise a second actuator configured for moving the first end of the fourth link relative to the support along a second trajectory (e.g. linear).

Preferably, one of the first and the second pivoting connection of both the third and fourth link are configured for limiting (a range of) a single rotational degree of freedom of the corresponding respective link. Preferably, the respective pivoting connection is configured to prevent a single rotational degree of freedom of the corresponding respective link For instance, such pivoting connection may comprise a single joint providing two degrees of freedom or a plurality of stacked joints providing just two degrees of freedom. The benefit of providing pivoting connections having limited rotational degrees of freedom is that it may improve robustness of the manipulator.

The first and second actuator mechanism may comprise a first and second prismatic joint, respectively, connected to the corresponding first end. The first and the second prismatic joint may be configured to provide linear first and second trajectories, respectively. Preferably, the first and the second actuator each provide a second actuating force configured to be co-linear with the corresponding trajectory. Additionally or alternatively, the prismatic joint and the corresponding trajectory may be configured co-linear. Such combination of guidance and imposition of displacement of the first ends provided by the prismatic joints limit the generation of moments and frictional forces, which would otherwise be caused when actuation forces are not aligned or co-linear with the prismatic joint. For example, the first and the second prismatic joint may extend (co-linearly) from a linearly actuated part of the corresponding (linear) actuator, such that the linear actuating force generated by the actuator is provided co-linearly to a central longitudinal axis of a moving part of the corresponding prismatic joint. The actuator may comprise a rack and a pinion, wherein a first part of the prismatic joint, such as a rod, extends from the rack and is configured for being guided along a second part of the prismatic joint, such as a linear bearing (e.g. a bushing) that may be (fixedly) connected to the support. The benefit of using a rod-shaped first part of the prismatic joint is that it provides a simple means that may for instance extend through a seal provided in a cover shielding sensitive components of the manipulator, such as motors and gears. For instance, the support may comprise such a cover.

Preferably, both the first and the second trajectory are substantially horizontal. Such a configuration is ideally suitable for embodiments wherein the manipulator is configured for charging a vehicle from an underside or a topside of the vehicle.

In a beneficial embodiment, the manipulator further comprises a base and a third actuator, such as a linear actuator (e.g. a rotary motor comprising means such as a rack and pinion arrangement or belt drive to provide a linear motion). The third actuator may be configured for moving the support along a (linear) third trajectory (e.g. substantially horizontal) relative to the base. This allows a larger initial misalignment between the vehicle and the manipulator. Furthermore, it enables moving the support along the third trajectory between a first (shielded) state, for instance wherein the support or the energy transfer unit is shielded from the environment for example by a housing, and a second (operating) state, for instance wherein the energy transfer unit can be positioned for charging a vehicle. Another benefit of such an embodiment is its so-called back-drivability, wherein a movement of the stage is induced by an external force applied (e.g. by the socket for instance provided on a vehicle) to the manipulator stage. In situations wherein such movements are induced in a direction substantially parallel to the third trajectory only the support has to be moved, which is only countered by the third actuator. In situations wherein such movements are induced within a plane substantially orthogonal to the third trajectory only the first and second actuating mechanisms have to be moved, which may only be countered by the first and second actuator.

The support may be configured to comprise the aforementioned cover for shielding. In a beneficial embodiment the motors of each of the actuators are configured to be shielded by the cover. Preferably, the gears of the first and the second actuator (e.g. rack and pinion) are provided in the cover. Furthermore, the pinion or gear of the third actuator may be provided on the support and the rack or belt of the third actuator may be provided on the base.

The manipulator may comprise a housing, which may be fixedly connected to the base. The third actuator may be configured for moving the support between a first state, wherein the support and preferably the first link or the energy transfer unit is completely received within the housing, and a second state, wherein the first link at least in part extends from a side of the housing. Beneficially, the third trajectory may have a directional component parallel to the first and second trajectory.

The manipulator may further comprise a third prismatic joint configured for guiding the movement of the support with respect to the base. The third prismatic joint may comprise a first part fixedly connected to the base and a second part fixedly connected to the support. Advantageously, the third prismatic joint comprises at least one, preferably two (parallel) telescopic guides for guiding the movement of the support with respect to the base. Preferably, each of the at least one telescopic guide has a stroke substantially parallel to the third trajectory. A telescopic guide may comprise any suitable type of extendable guide. It may for instance comprise longitudinal elements configured for sliding into one another, but preferably comprises longitudinal elements configured for sliding alongside one another.

The first and second trajectory may define a first plane. Preferably, the first trajectory, the second trajectory and a projection of the third trajectory on the first plane each have with respect to each other one, one of a list of: an acute angle (α, β, γ) of less than <NUM> degrees, preferably less than <NUM> degrees, more preferably less than <NUM> degrees and even more preferably less than <NUM> degrees and no angle. This facilitates shielding of actuators and other moving parts of the manipulator, since all trajectories comprise at least one common directional component.

Additionally or alternatively, the first end of the first link is provided in a second plane parallel to the first plane, wherein the second plane is other than the first plane. Preferably, at least one of the first end of the third link, the second end of the third link, the first end of the fourth link and the second end of the fourth link is configured outside the second plane. This enables a defined movement from the first joint with respect to the support under all situations. In one example, the first link comprises a protrusion protruding away from the first longitudinal axis (e.g. the first link comprises a shoulder), wherein the protrusion is configured for pivotally connecting the second end of the third link, and the second end of the fourth link. The first end of the second link may be configured outside the second plane. Embodiments, wherein the first link comprises a protrusion protruding away from the first longitudinal axis, are also suitable for actuating mechanisms alternative to actuating mechanisms comprising a third and a fourth link.

The first end of the first link may be configured equidistant from the first trajectory and the second trajectory. Preferably, the first end of the second link is configured in closer proximity to the first trajectory than the second trajectory. In such an arrangement the second link can function as a push or pull rod for substantially maintaining an orientation of the stage. In one example of such a configuration, the first link and the second link each comprises a longitudinal axis and wherein the longitudinal axis of the first link is substantially parallel to the longitudinal axis of the second link.

The first end of the first link may provide a first pivoting connection to the support, wherein the pivoting connection is configured for limiting (a range of) a single rotational degree of freedom of the first link. Preferably, the pivoting connection may be configured to prevent a single rotational degree of freedom. The single rotational degree of freedom may be configured to provide a reaction-torque in response to the first actuating force of each of the first and second actuating mechanism. The reaction-torque provided by the pivoting connection preferably comprises a direction having a directional component orthogonal to the direction of the torque provided by the first actuating mechanism and the second actuating mechanism. This may prevent tilting of the stage about the longitudinal axis of the first link and thereby simplifies alignment of the energy transfer unit.

The second end of the first link may provide a second pivoting connection to the stage. The second pivoting connection of the first link may define an axis of rotation of the stage, wherein the second pivoting connection may be configured for providing a single rotational degree of freedom about the axis of rotation. Preferably, the stage comprises a sidewall being at least in part circular about the axis of rotation. This may shield the second end of the first link in any orientation of the first link.

The energy transfer unit may be connected to the stage at any location, for instance at a first position radially extending from the axis of rotation. Preferably, the energy transfer unit is pivotally connected to the stage such that it can be aligned, for instance by contacting a surface of the vehicle, along to multiple axes of rotation. The energy transfer unit may further comprise communicating means for providing communication, for instance regarding charge levels, between the vehicle and the manipulator. Additionally or alternatively, the energy transfer unit may comprise sensors or beacons for guiding the energy transfer unit of the manipulator towards the vehicle.

To limit the exposure of features of the manipulator to the environment, the first link may provide a conduit parallel to the first longitudinal axis (i.e. an axis between the first end and the second end of the first link). The conduit may be configured for providing passage to the second link. Embodiments of a manipulator according to the present invention may comprise an energy cable configured to transfer energy along the first link to the end effector. The conduit of the first link may additionally or alternatively provide passage for the energy cable. A stage configured to shield the second end of the first link, for instance as described before, may also be configured to shield the conduit and thereby for instance the second link or the energy cable.

According to a second aspect of the invention the object is achieved by a charging station according to the appended claims. A charging station according to the present invention achieves the object of the invention in a similar way as a manipulator according to the present invention.

In the present disclosure, a relative movement of one end of a link with respect to another end of such link is defined by a change in orientation of the one end with respect to the other end according to a stationary (e.g. with respect to the support) cartesian coordinate system, or in other words any movement changing a direction of a longitudinal axis defined by the one end and the other end. Such relative movement may comprise a rotation of such link or an unequal translational movements of the one end with respect to the other end, but does not comprise movements consisting of equal translational movements in terms of distance and direction of the one end and the other end. For instance, pivoting the first link about the first pivoting connection moves the second end of the first link relative to the first end of the first link.

Referring to <FIG>, a manipulator <NUM> according to the present invention comprises a support <NUM> and a first link <NUM> configured to pivot with respect to the support <NUM> to position an end effector <NUM> (e.g. an energy transfer unit) in an operating volume when the manipulator <NUM> is in an operating or second state (also see <FIG> and <FIG>). Therefore, the first link <NUM> is pivotally connected to the support <NUM> by a pivoting connection <NUM> provided at a first end <NUM> of the first link <NUM> and pivotally connected to a stage <NUM> comprising the end effector <NUM> at a second end <NUM> of the first link <NUM>. Furthermore, a first and a second actuating mechanism <NUM>, <NUM> provide an actuatable connection configured to move the stage <NUM> relative to the support <NUM> via respective forces acting on the first link <NUM>, preferably near the first end <NUM> of the first link <NUM>. In the operating state, the support <NUM> may extend from a side of a housing <NUM>. A hatch <NUM> may be provided configured to open the side of the housing <NUM> and allow the support <NUM> to extend from the housing <NUM>.

Further referring to <FIG>, the first and second actuating mechanism <NUM>, <NUM> may comprise a third and a fourth link <NUM>, <NUM>, respectively. The third and fourth link <NUM>, <NUM> each comprise a first end <NUM>, <NUM> and a second end <NUM>, <NUM>. The second ends <NUM>, <NUM> are pivotally connected to the first link <NUM>, possibly at offset positions, even though this is not a requirement. The first ends <NUM>, <NUM> are configured to move (e.g. translate) with respect to the support <NUM> along a first and a second preferably linear trajectory <NUM>, <NUM>, respectively. This movement along the first and second trajectory <NUM>, <NUM> results in a pivoting movement of the first link <NUM> about pivoting connection <NUM>, with respect to the support <NUM>. Preferably, the second ends <NUM>, <NUM> the third and fourth link <NUM>, <NUM> are each pivotally connected to the first link <NUM> near the first end <NUM> of the first link for limiting the extent to which the third and fourth link <NUM>, <NUM> extend into the environment.

Referring to <FIG>, the first and second actuating mechanisms <NUM>, <NUM> are each configured to exert a force on the first link <NUM>, in the pivotal connections at the second ends <NUM>, <NUM> of the third and fourth links, respectively. These forces have opposite directional components, particularly in projection on a horizontal plane, allowing the first link to be moved about a vertical axis A defined by pivotal connection <NUM> along a direction A'. Referring to <FIG>, the pivotal connection <NUM> of the first link <NUM> to the support <NUM> and the pivotal connections of the second ends <NUM> and <NUM> of the third and fourth links on the first link <NUM> are preferably arranged in offset horizontal planes. This allows the first and second actuating mechanisms to move the first link <NUM> about a horizontal axis B defined by pivotal connection <NUM> along another direction B'.

Actuating the first and second actuating mechanisms <NUM>, <NUM> simultaneously may result in a pulling or a pushing force exerted on the first link <NUM>. In response, the second end <NUM> of the first link <NUM>, the stage <NUM> and end effector <NUM> will be moved relative to the support <NUM> in a direction orthogonal to a plane defined by the first and second trajectory <NUM>, <NUM>, for instance away or towards a mounting surface (e.g. horizontal ground surface). Differentially actuating the first and second actuating mechanisms may, optionally in addition result in a movement of the second end <NUM> of the first link <NUM> in a direction having a directional component parallel to the plane defined by the first and second trajectory <NUM>, <NUM>, for instance sideways relative to the mounting surface (not shown).

Each of the first and second actuating mechanism <NUM>, <NUM> may further comprise a prismatic joint <NUM>, <NUM> arranged in parallel to the first and second trajectory <NUM>, <NUM>, respectively. The prismatic joints can be pivotally connected to the first end <NUM>, <NUM> of the corresponding link <NUM>, <NUM>. Such prismatic joints <NUM>, <NUM> may each comprise a rod <NUM> and two bushings <NUM>, <NUM>, wherein the rod <NUM> is configured for sliding along the bushings <NUM>, <NUM>. The rod <NUM> extending between two bushings <NUM>, <NUM> may be directly pivotally connected to the first end <NUM>, <NUM> of the corresponding link <NUM>, <NUM>.

Each of the first and second actuating mechanism <NUM>, <NUM> may each further comprise an actuator <NUM>, such as a linear motor or a rotary motor comprising a means <NUM> for converting a rotary motion to a linear motion, for instance using a rack and pinion or a belt drive. The linearly actuated part of the actuating means <NUM> may be connected co-linearly to the rod <NUM> to actuate the linear movement of the rod <NUM>.

The manipulator <NUM> may comprise a base <NUM> and a third actuator <NUM>. The third actuator <NUM> is configured to move the support along a third trajectory <NUM> with respect to the base <NUM> between a first state (see <FIG>) and a second state (see <FIG>, <FIG> and <FIG>). Preferably, the third trajectory <NUM> is linear and substantially parallel to a longitudinal axis of the first link <NUM> in the first state. The manipulator <NUM> may further comprise one, preferably two prismatic joints <NUM> (e.g. telescopic guides) for guiding the movement of the support <NUM> along the third trajectory <NUM>. Preferably, the third trajectory <NUM> is a linear trajectory parallel to the first and second linear trajectories <NUM>, <NUM>.

The first, second and third actuators <NUM>, <NUM> may comprise motors, such as rotary motors, fixedly connected to the support <NUM>. The actuators may further comprise a means <NUM>, <NUM> for converting a rotary motion to a linear motion, for instance using a rack and pinion or a belt drive. The first and second actuators <NUM> preferably comprise a rack and pinion. The third actuator <NUM> preferably also comprises a rack and pinion.

The support <NUM> may comprise a cover for shielding sensitive parts of the manipulator <NUM>, such as parts of the first actuating mechanisms <NUM>, parts of the second actuating mechanisms <NUM>, parts of the third actuator <NUM>, for example motors and means <NUM>, <NUM> for converting a rotary motion to a linear motion (e.g. gears), which may for instance otherwise be exposed to the external environment in the second state.

The manipulator may comprise a housing <NUM> connected to the base <NUM> configured for shielding the first link <NUM>, the stage <NUM> and the end effector <NUM> of the manipulator <NUM> in the first state. The cover <NUM> may further comprise a hatch <NUM> configured at a side of the cover <NUM> wherefrom the first link <NUM> may protrude in the second state. The hatch <NUM> being configured to move between a closed state in the first state, wherein the hatch <NUM> shields the first link <NUM>, and an opened state in the second state, wherein the first link <NUM> may extend from the cover <NUM>.

Further referring to <FIG> and <FIG>, the manipulator <NUM> may further comprise a second link <NUM> having a first end <NUM> pivotally connected to the support <NUM> and a second end <NUM> pivotally connected to the stage <NUM> at a location offset from a pivotal connection <NUM> of the second end <NUM> of the first link <NUM> to the stage. The pivotal connection <NUM> of the second end <NUM> of the first link <NUM> to the stage may provide an axis of rotation C of the stage for rotating the stage along a direction C'. Preferably, the first end <NUM> of the second link <NUM> is connected to the support <NUM> at a location offset from the pivotal connection <NUM> connecting the first end <NUM> of the first link <NUM> to the support <NUM>. Preferably, the first link and the second link <NUM>, <NUM> each define a longitudinal axis between the corresponding first and second ends, which longitudinal axes are substantially parallel. The first and second link <NUM>, <NUM> may be configured to define a parallelogram or a trapezoid, wherein it is not required that all edges necessarily lie within a same plane. Such second link <NUM> substantially maintains an orientation <NUM> of the stage <NUM> with respect to the environment, when the first link <NUM> is moved sideways by the first and second actuating mechanisms <NUM>, <NUM> (see <FIG> and <FIG>).

Claim 1:
Manipulator (<NUM>) for positioning an end effector (<NUM>) for charging vehicles, comprising:
a support (<NUM>),
a stage (<NUM>) comprising the end effector,
a first link (<NUM>) comprising a first end (<NUM>) providing a first pivoting connection (<NUM>) connected to the support and a second end (<NUM>) providing a second pivoting connection (<NUM>) connected to the stage, wherein the first link defines a first longitudinal axis between the first end and the second end,and
a second link (<NUM>) comprising a first end (<NUM>) providing a first pivoting connection connected to the support and a second end (<NUM>) providing a second pivoting connection connected to the stage at a first position offset from the second pivoting connection of the first link,
characterised in that the manipulator further comprises:
a first (<NUM>) and a second (<NUM>) actuating mechanism providing an actuatable connection between the stage and the support through the first link, each of the first and the second actuating mechanisms configured to exert a first actuating force on the first link for moving the second end of the first link through a volume.