A hydraulic machine comprising: an undercarriage, a rotating structure rotatably mounted on the undercarriage and configured to rotate with and with respect to the undercarriage, a first controller configured to receive user input, a user interface configured to accept commands from a user and output a command signal to the first controller, a first gyroscope fixed to the rotating structure and electrically connected to the first controller and configured to provide a data signal of rotation information of the rotating structure to the first controller, the first gyroscope having an axis of rotation, characterised in that the machine includes: a variable displacement hydraulic swing pump operable by a prime mover, a hydraulic swing motor for performing a swing function of the machine, an accumulator, a swing control valve assembly disposed in a first hydraulic path extending from the swing pump to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump to a first side of the swing motor and a second position fluidly connecting the swing pump to a second side of the swing motor, an accumulator control valve having an open position fluidly connecting the accumulator to the first hydraulic path at an accumulator control valve connection point and a closed position fluidly isolating the accumulator from the first hydraulic path, and an isolation valve disposed in the fluid pathway between the accumulator control valve connection point and the swing control valve, the isolation valve having an open position fluidly connecting the swing pump to the swing motor, and a closed position fluidly isolating the accumulator and the swing pump from the swing motor, in which the axis of rotation of the first gyroscope is parallel to the axis of rotation of the rotating structure, and in which the first controller is configured to generate a control signal to control the rotating structure and cause the rotating structure to rotate with respect to the undercarriage based on the command signal from the user interface and the data signal from the first gyroscope. an undercarriage, a rotating structure rotatably mounted on the undercarriage and configured to rotate with and with respect to the undercarriage, a first controller configured to receive user input, a user interface configured to accept commands from a user and output a command signal to the first controller, a first gyroscope fixed to the rotating structure and electrically connected to the first controller and configured to provide a data signal of rotation information of the rotating structure to the first controller, the first gyroscope having an axis of rotation, characterised in that the machine includes: a variable displacement hydraulic swing pump operable by a prime mover, a hydraulic swing motor for performing a swing function of the machine, an accumulator, a swing control valve assembly disposed in a first hydraulic path extending from the swing pump to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump to a first side of the swing motor and a second position fluidly connecting the swing pump to a second side of the swing motor, an accumulator control valve having an open position fluidly connecting the accumulator to the first hydraulic path at an accumulator control valve connection point and a closed position fluidly isolating the accumulator from the first hydraulic path, and an isolation valve disposed in the fluid pathway between the accumulator control valve connection point and the swing control valve, the isolation valve having an open position fluidly connecting the swing pump to the swing motor, and a closed position fluidly isolating the accumulator and the swing pump from the swing motor, in which the axis of rotation of the first gyroscope is parallel to the axis of rotation of the rotating structure, and in which the first controller is configured to generate a control signal to control the rotating structure and cause the rotating structure to rotate with respect to the undercarriage based on the command signal from the user interface and the data signal from the first gyroscope. a variable displacement hydraulic swing pump operable by a prime mover, a hydraulic swing motor for performing a swing function of the machine, an accumulator, a swing control valve assembly disposed in a first hydraulic path extending from the swing pump to the swing motor, the swing control valve assembly having a first position fluidly connecting the swing pump to a first side of the swing motor and a second position fluidly connecting the swing pump to a second side of the swing motor, an accumulator control valve having an open position fluidly connecting the accumulator to the first hydraulic path at an accumulator control valve connection point and a closed position fluidly isolating the accumulator from the first hydraulic path, and an isolation valve disposed in the fluid pathway between the accumulator control valve connection point and the swing control valve, the isolation valve having an open position fluidly connecting the swing pump to the swing motor, and a closed position fluidly isolating the accumulator and the swing pump from the swing motor, in which the axis of rotation of the first gyroscope is parallel to the axis of rotation of the rotating structure, and in which the first controller is configured to generate a control signal to control the rotating structure and cause the rotating structure to rotate with respect to the undercarriage based on the command signal from the user interface and the data signal from the first gyroscope.