Abstract: A measurement strut for measuring a separation between two relatively moveable support members of a machine (for example, a robot arm). The strut is removably couplable between the two support members and is adapted to become at least partially decoupled from at least one of the support members when a compressive force developed in the strut by relative movement of the support members is greater than a predetermined threshold. By becoming at least partially decoupled from at least one of the support members, at least some of any excess relative movement of the support members towards each other can be absorbed, thereby helping to prevent damage being caused to the strut by attempting to compress the strut beyond its minimum range of travel.

Abstract: A coordinate positioning machine includes a plurality of drive axes, each being a rotary or linear drive axis, for positioning a platform within a working volume of the machine, and a separate linear counterbalance axis for counterbalancing the platform. With this arrangement the counterbalance axis can be substantially invariant to changes in orientation of the drive axes and can be counterbalanced by a simple counterweight. Also, an arrangement wherein the counterbalance axes and force generator are arranged so horizontal movement of the platform causes substantially no net movement of and/or no work to be done on the generator. Also, an arrangement wherein a series of counterbalance axes has at least one rotary counterbalance axis, and the generator is arranged behind or at a predetermined distance from the counterbalance axis. Also, an arrangement having a series of counterbalance axes with at most one rotary counterbalance axis between the generator and ground.

Abstract: A coordinate positioning machine includes a plurality of drive axes, each being a rotary or linear drive axis, for positioning a platform within a working volume of the machine, and a separate linear counterbalance axis for counterbalancing the platform. With this arrangement the counterbalance axis can be substantially invariant to changes in orientation of the drive axes and can be counterbalanced by a simple counterweight. Also, an arrangement wherein the counterbalance axes and force generator are arranged so horizontal movement of the platform causes substantially no net movement of and/or no work to be done on the generator. Also, an arrangement wherein a series of counterbalance axes has at least one rotary counterbalance axis, and the generator is arranged behind or at a predetermined distance from the counterbalance axis. Also, an arrangement having a series of counterbalance axes with at most one rotary counterbalance axis between the generator and ground.

Abstract: A coordinate positioning machine includes a plurality of drive axes, each being a rotary or linear drive axis, for positioning a platform within a working volume of the machine, and a separate linear counterbalance axis for counterbalancing the platform. With this arrangement the counterbalance axis can be substantially invariant to changes in orientation of the drive axes and can be counterbalanced by a simple counterweight. Also, an arrangement wherein the counterbalance axes and force generator are arranged so horizontal movement of the platform causes substantially no net movement of and/or no work to be done on the generator. Also, an arrangement wherein a series of counterbalance axes has at least one rotary counterbalance axis, and the generator is arranged behind or at a predetermined distance from the counterbalance axis. Also, an arrangement having a series of counterbalance axes with at most one rotary counterbalance axis between the generator and ground.

Abstract: A coordinate positioning arm includes: a base end and a head end; a drive frame for moving the head end relative to the base end; and a metrology frame for measuring a position and orientation of the head end relative to the base end. The drive frame includes a plurality of drive axes arranged in series between the base end and the head end. The metrology frame includes a plurality of metrology axes arranged in series between the base end and the head end. The metrology frame is adapted and arranged to be substantially separate and/or independent from the drive frame, for example by supporting the metrology frame substantially only at the base end and head end and by providing the metrology frame with sufficient degrees of freedom (via the metrology axes) to avoid creating an additional constraint between the metrology frame and the drive frame.

Abstract: A coordinate positioning machine that includes: a structure moveable within a working volume of the machine, a hexapod metrology arrangement for measuring the position of the structure within the working volume, and a non-hexapod drive arrangement for moving the structure around the working volume. Also, a coordinate positioning machine including a structure moveable within a working volume of the machine, a drive arrangement for moving the structure around the working volume in fewer than six degrees of freedom, and a metrology arrangement for measuring the position of the structure within the working volume in more degrees of freedom than the drive arrangement.

Abstract: A coordinate positioning machine includes a drive frame and a metrology frame. The drive frame includes a drive arrangement for moving a structure around a working volume of the machine. The metrology frame includes a metrology arrangement for measuring the position of the structure within the working volume. The metrology arrangement is a hexapod metrology arrangement and the drive arrangement is a non-hexapod drive arrangement. The metrology frame has a coefficient of thermal expansion that is lower than that of the drive frame. The drive frame is coupled to the metrology frame via a coupling arrangement which prevents at least some distortion associated with any extra thermal expansion and contraction of the drive frame from being transferred to the metrology frame. The drive arrangement moves the structure around the working volume, and the metrology arrangement measures the position of the structure within the working volume.

Abstract: A coordinate positioning arm includes: a base end and a head end; a drive frame for moving the head end relative to the base end; and a metrology frame for measuring a position and orientation of the head end relative to the base end. The drive frame includes a plurality of drive axes arranged in series between the base end and the head end. The metrology frame includes a plurality of metrology axes arranged in series between the base end and the head end. The metrology frame is adapted and arranged to be substantially separate and/or independent from the drive frame, for example by supporting the metrology frame substantially only at the base end and head end and by providing the metrology frame with sufficient degrees of freedom (via the metrology axes) to avoid creating an additional constraint between the metrology frame and the drive frame.

Abstract: A coordinate positioning machine includes a drive frame and a metrology frame. The drive frame includes a drive arrangement for moving a structure around a working volume of the machine. The metrology frame includes a metrology arrangement for measuring the position of the structure within the working volume. The metrology arrangement is a hexapod metrology arrangement and the drive arrangement is a non-hexapod drive arrangement. The metrology frame has a coefficient of thermal expansion that is lower than that of the drive frame. The drive frame is coupled to the metrology frame via a coupling arrangement which prevents at least some distortion associated with any extra thermal expansion and contraction of the drive frame from being transferred to the metrology frame. The drive arrangement moves the structure around the working volume, and the metrology arrangement measures the position of the structure within the working volume.

Abstract: A non-Cartesian coordinate positioning machine is provided that comprises an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine, and a constraint member associated with the extendable leg assembly for providing a predetermined part of the extendable leg assembly with substantially a same orientation relative to gravity for a same position of the component within the working volume. In a preferred embodiment, the orientation relative to gravity is maintained substantially constant, so that a plane defined by the predetermined part is substantially aligned with gravity, as the component is moved around the working volume.

Abstract: A non-Cartesian coordinate positioning machine that includes an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine. The extendable leg assembly includes a first member and a second member which move relative to one another when the extendable leg assembly changes length. The first member including an axial arrangement of magnets forming part of a linear motor for extending and retracting the extendable leg assembly, and at least one resilient member for absorbing at least some of any axial thermal expansion or contraction of the magnets in use.

Abstract: A coordinate positioning machine that includes: a structure moveable within a working volume of the machine, a hexapod metrology arrangement for measuring the position of the structure within the working volume, and a non-hexapod drive arrangement for moving the structure around the working volume. Also, a coordinate positioning machine including a structure moveable within a working volume of the machine, a drive arrangement for moving the structure around the working volume in fewer than six degrees of freedom, and a metrology arrangement for measuring the position of the structure within the working volume in more degrees of freedom than the drive arrangement.

Abstract: A coordinate positioning machine that includes: a structure moveable within a working volume of the machine, a hexapod metrology arrangement for measuring the position of the structure within the working volume, and a non-hexapod drive arrangement for moving the structure around the working volume. Also, a coordinate positioning machine including a structure moveable within a working volume of the machine, a drive arrangement for moving the structure around the working volume in fewer than six degrees of freedom, and a metrology arrangement for measuring the position of the structure within the working volume in more degrees of freedom than the drive arrangement.

Abstract: A non-Cartesian coordinate positioning machine that includes an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine. The extendable leg assembly includes a first member and a second member which move relative to one another when the extendable leg assembly changes length. The first member including an axial arrangement of magnets forming part of a linear motor for extending and retracting the extendable leg assembly, and at least one resilient member for absorbing at least some of any axial thermal expansion or contraction of the magnets in use.

Abstract: A non-Cartesian coordinate positioning machine is provided that comprises an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine, and a constraint member associated with the extendable leg assembly for providing a predetermined part of the extendable leg assembly with substantially a same orientation relative to gravity for a same position of the component within the working volume. In a preferred embodiment, the orientation relative to gravity is maintained substantially constant, so that a plane defined by the predetermined part is substantially aligned with gravity, as the component is moved around the working volume.

Abstract: A non-Cartesian coordinate positioning machine that includes an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine. The extendable leg assembly includes a first member and a second member which move relative to one another when the extendable leg assembly changes length. The first member including an axial arrangement of magnets forming part of a linear motor for extending and retracting the extendable leg assembly, and at least one resilient member for absorbing at least some of any axial thermal expansion or contraction of the magnets in use.

Abstract: A positioning apparatus comprising first and second relatively moveable members, and a linear motor comprising at least one elongate stator assembly and at least one armature assembly respectively mounted to the first and second moveable members for effecting relative movement of the first and second moveable members, configured so at to permit longitudinal expansion and/or contraction of the at least one elongate stator assembly and/or of the at least one armature assembly relative to its respective member.

Abstract: A non-Cartesian coordinate positioning machine is provided that comprises an extendable leg assembly for positioning a component such as a measurement probe within a working volume of the machine, and a constraint member associated with the extendable leg assembly for providing a predetermined part of the extendable leg assembly with substantially a same orientation relative to gravity for a same position of the component within the working volume. In a preferred embodiment, the orientation relative to gravity is maintained substantially constant, so that a plane defined by the predetermined part is substantially aligned with gravity, as the component is moved around the working volume.

Abstract: A coordinate positioning machine that includes: a structure moveable within a working volume of the machine, a hexapod metrology arrangement for measuring the position of the structure within the working volume, and a non-hexapod drive arrangement for moving the structure around the working volume. Also, a coordinate positioning machine including a structure moveable within a working volume of the machine, a drive arrangement for moving the structure around the working volume in fewer than six degrees of freedom, and a metrology arrangement for measuring the position of the structure within the working volume in more degrees of freedom than the drive arrangement.

Abstract: A coordinate positioning apparatus comprising first and second relatively moveable bodies, at least the first body comprising at least one sheet or plate of material arranged to provide a load-bearing structure comprising a plurality of planar load-bearing members and on which at least one member is mounted to the first body via a mount which is coupled to at least three, non-parallel planar load-bearing members of the first body, such that the planes of said at least three non-parallel planar load-bearing members intersect each other at a common point.