An actuator system comprising: a shared member (521/721) configured and arranged for rotary movement about a first axis (544/744) relative to a reference structure (520/720); a controlled element (525/725) configured and arranged for rotary movement about a second axis (526/726) relative to said reference structure; a first linkage (556, 546, 552 / 756, 746, 752) connected to said controlled element at a first element connection (536/736) offset from said second axis and extending from said first element connection to a first output shaft connection (594/794) offset from said first axis; a second linkage (555, 547, 553 / 755, 747, 753) connected to said controlled element at a second element connection (535/735) offset from said second axis and extending from said second element connection to a second output shaft connection (593, 793) offset from said first axis; characterised by a first output shaft (542/742) connected to said first linkage and configured and arranged for rotary movement about the first axis (544/744) relative to said shared member; a first rotary actuator (540/740) configured and arranged to control rotation of said first output shaft (542/742), and whose stator is mounted on the shared member (521/721); a second output shaft (543/743) connected to said second linkage and configured and arranged for rotary movement about the first axis (544/744) relative to said shared member; a second rotary actuator (541/741) configured and arranged to control rotation of said second output shaft, and whose stator is mounted on the shared member (521/721); said first rotary actuator (540/740), first output shaft (542/742) and first linkage configured and arranged to rotate said controlled element (525/725) about said second axis (526/726) relative to said reference structure when said second rotary actuator (541/741) operatively locks rotation of said second output shaft (542/742, 543/743) about said first axis (544/744) relative to said shared member (521/721); and said shared member (521/721), said first and second output shafts (542/742, 543/743) and said first and second rotary actuators (540/740, 541/741) configured and arranged such that said shared member (521/721) rotates about said first axis (544/744) when said second rotary actuator (541/741) operatively locks rotation of said second output shaft (543/743) about said first axis (544/744) relative to said shared member (521/721). a shared member (521/721) configured and arranged for rotary movement about a first axis (544/744) relative to a reference structure (520/720); a controlled element (525/725) configured and arranged for rotary movement about a second axis (526/726) relative to said reference structure; a first linkage (556, 546, 552 / 756, 746, 752) connected to said controlled element at a first element connection (536/736) offset from said second axis and extending from said first element connection to a first output shaft connection (594/794) offset from said first axis; a second linkage (555, 547, 553 / 755, 747, 753) connected to said controlled element at a second element connection (535/735) offset from said second axis and extending from said second element connection to a second output shaft connection (593, 793) offset from said first axis; characterised by a first output shaft (542/742) connected to said first linkage and configured and arranged for rotary movement about the first axis (544/744) relative to said shared member; a first rotary actuator (540/740) configured and arranged to control rotation of said first output shaft (542/742), and whose stator is mounted on the shared member (521/721); a second output shaft (543/743) connected to said second linkage and configured and arranged for rotary movement about the first axis (544/744) relative to said shared member; a second rotary actuator (541/741) configured and arranged to control rotation of said second output shaft, and whose stator is mounted on the shared member (521/721); said first rotary actuator (540/740), first output shaft (542/742) and first linkage configured and arranged to rotate said controlled element (525/725) about said second axis (526/726) relative to said reference structure when said second rotary actuator (541/741) operatively locks rotation of said second output shaft (542/742, 543/743) about said first axis (544/744) relative to said shared member (521/721); and said shared member (521/721), said first and second output shafts (542/742, 543/743) and said first and second rotary actuators (540/740, 541/741) configured and arranged such that said shared member (521/721) rotates about said first axis (544/744) when said second rotary actuator (541/741) operatively locks rotation of said second output shaft (543/743) about said first axis (544/744) relative to said shared member (521/721).