A torque sensor arrangement 150 for attachment between a first part or carrier 104 and a second part or distal arm frame 101 to sense torque therebetween comprises an interface member in the form of bevel gear 108 having on its exterior an engagement configuration of teeth 151 for rotationally engaging the first part 104 via worm 113； a torsion member comprising a deflectable body 156 attached at one end thereof to the interface member 108 and comprising, at the other end of the deflectable body 156, an engagement configuration for rotationally engaging the second part 101 and a deflection sensor or strain gauge 160 attached to the deflectable body 160, the interface member 108 defines a rigid sleeve 153 extending around the deflectable body 156 and the torque sensor arrangement further comprises a bushing 161 located between and in contact with both the sleeve 153 and the deflectable body 156. This reduces friction between the sleeve 153 and the deflectable body 156 whilst avoiding applying shear forces to the deflectable body 156.
