Sub,
F.
,
Varol,
H. A.
, and
Goldfarb,
M.
, 2010, “
Upslope Walking With a Powered Knee and Ankle Prosthesis: Initial Results With an Amputee Subject,” IEEE Trans. Neural Syst. Rehabil. Eng.,
19(1), pp. 71–78.

[PubMed]
Harvey,
Z.
,
Potter,
B. K.
,
Vandersea,
J.
, and
Wolf,
E.
, 2011, “
Prosthetic Advances,” J. Surg. Orthop. Adv.,
21(1), pp. 58–64

http://www.armdynamics.com/caffeine/uploads/files/21-1-9.pdf.

Martinez-Villalpando,
E. C.
,
Weber,
J.
,
Elliott,
G.
, and
Herr,
H.
, 2008, “
Design of an Agonist-Antagonist Active Knee Prosthesis,” IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics, Scottsdale, AZ, Oct. 19–22, pp. 529–534.

Au,
S. K.
,
Herr,
H.
,
Weber,
J.
, and
Martinez-Villalpando,
E. C.
, 2007, “
Powered Ankle-Foot Prosthesis for the Improvement of Amputee Ambulation,” 29th Annual IEEE Conference on Engineering in Medicine and Biology Society (EMBS), Lyon, France, Aug. 22–26, pp. 3020–3026.

Au,
S. K.
,
Weber,
J.
, and
Herr,
H.
, 2007, “
Biomechanical Design of a Powered Ankle Foot Prosthesis,” IEEE International Conference on Rehabilitation Robotics (ICORR), Noordwijk, The Netherlands, June 13–15, pp. 298–303.

Zhao,
H.
,
Kolathaya,
S.
, and
Ames,
A. D.
, 2014, “
Quadratic Programming and Impedance Control for Transfemoral Prosthesis,” International Conference on Robotics and Automation (ICRA), Hong Kong, China, May 31–June 7, pp. 1341–1347.

Gregg,
R. D.
,
Lenzi,
T.
,
Hargrove,
L. J.
, and
Sensinger,
J. W.
, 2014, “
Virtual Constraint Control of a Powered Prosthetic Leg: From Simulation to Experiments With Transfemoral Amputees,” IEEE Trans. Rob.,
30(6), pp. 1455–1471.

[CrossRef]
Young,
A. J.
,
Simon,
A. M.
, and
Hargrove,
L. J.
, 2014, “
A Training Method for Locomotion Mode Prediction Using Powered Lower Limb Prostheses,” IEEE Trans. Neural Syst. Rehabil. Eng.,
22(3), pp. 671–677.

[CrossRef] [PubMed]
Murakami,
T.
,
Nakamura,
R.
,
Yu,
F.
, and
Ohnishi,
K.
, 1993, “
Force Sensorless Impedance Control by Disturbance Observer,” IEEE Power Conversion Conference, Yokohama, Japan, Apr. 19–21, pp. 352–357.

Simpson,
J. W. L.
,
Cook,
C. D.
, and
Li,
Z.
, 2002, “
Sensorless Force Estimation for Robots With Friction,” Australasian Conference on Robotics and Automation, Auckland, New Zealand, Nov. 27–29, pp. 94–99

https://pdfs.semanticscholar.org/17ad/b33f0e6f6ceaa05dbecbe5781232709967b0.pdf.

Phong,
L. D.
,
Choi,
J.
,
Lee,
W.
, and
Kang,
S.
, 2015, “
A Novel Method for Estimating External Force: Simulation Study With a 4-DOF Robot Manipulator,” Int. J. Precis. Eng. Manuf.,
16(4), pp. 755–766.

[CrossRef]
Hacksel,
P. J.
, and
Salcudean,
S. E.
, 1994, “
Estimation of Environment Forces and Rigid-Body Velocities Using Observers,” IEEE International Conference on Robotics and Automation (ICRA), San Diego, CA, May 8–13, pp. 931–936.

Rigatos,
G. G.
, 2012, “
A Derivative-Free Kalman Filtering Approach to State Estimation-Based Control of a Class of Nonlinear Systems,” IEEE Trans. Ind. Electron.,
59(10), pp. 3987–3997.

[CrossRef]
Sarkka,
S.
, 2007, “
On Unscented Kalman Filtering for State Estimation of Continuous-Time Nonlinear Systems,” IEEE Trans. Autom. Control,
52(9), pp. 1631–1641.

[CrossRef]
Julier,
S. J.
,
Uhlmann,
J. K.
, and
Durrant-Whyte,
H. F.
, 1995, “
A New Approach for Filtering Nonlinear Systems,” American Control Conference (ACC), Seattle, WA, June 21–23, pp. 1628–1632.

Fakoorian,
S. A.
,
Simon,
D.
,
Richter,
H.
, and
Azimi,
V.
, 2016, “
Ground Reaction Force Estimation in Prosthetic Legs With an Extended Kalman Filter,” IEEE International Systems Conference (SysCon), Orlando, FL, Apr. 18–21, pp. 338–343.

Richter,
H.
, and
Simon,
D.
, 2014, “
Robust Tracking Control of a Prosthesis Test Robot,” ASME J. Dyn. Syst. Meas. Control,
136(3), p. 031011.

[CrossRef]
van den Bogert,
A. J.
,
Geijtenbeek,
T.
,
Even-Zohar,
O.
,
Steenbrink,
F.
, and
Hardin,
E. C.
, 2013, “
A Real-Time System for Biomechanical Analysis of Human Movement and Muscle Function,” Med. Biol. Eng. Comput.,
51(10), pp. 1069–1077.

[CrossRef] [PubMed]
Azimi,
V.
,
Simon,
D.
, and
Richter,
H.
, 2015, “
Stable Robust Adaptive Impedance Control of a Prosthetic Leg,” ASME Paper No. DSCC2015-9794.

Richter,
H.
,
Simon,
D.
,
Smith,
W. A.
, and
Samorezov,
S.
, 2015, “
Dynamic Modeling, Parameter Estimation and Control of a Leg Prosthesis Test Robot,” Appl. Math. Modell.,
39(2), pp. 559–573.

[CrossRef]
Mohammadi,
H.
, and
Richter,
H.
, 2015, “
Robust Tracking/Impedance Control: Application to Prosthetics,” American Control Conference (ACC), Chicago, IL, July 1–3, pp. 2673–2678.

Azimi,
V.
,
Simon,
D.
,
Richter,
H.
, and
Fakoorian,
S. A.
, 2016, “
Robust Composite Adaptive Transfemoral Prosthesis Control With Non-Scalar Boundary Layer Trajectories,” American Control Conference (ACC), Boston, MA, July 6–8, pp. 3002–3007.

Warner,
H.
,
Simon,
D.
,
Mohammadi,
H.
, and
Richter,
H.
, 2016, “
Switched Robust Tracking/Impedance Control for an Active Transfemoral Prosthesis,” American Control Conference (ACC), Boston, MA, July 6–8, pp. 2187–2192.

van der Merwe,
R.
, and
Wan,
E. A.
, 2001, “
The Square-Root Unscented Kalman Filter for State and Parameter-Estimation,” IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP'01), Salt Lake City, UT, May 7–11, pp. 3461–3464.

Simon,
D.
, 2006, Optimal State Estimation: Kalman, H Infinity, and Nonlinear Approaches,
Wiley, Hoboken, NJ.

[CrossRef]
Safonov,
M.
, and
Athans,
M.
, 1978, “
Robustness and Computational Aspects of Nonlinear Stochastic Estimators and Regulators,” IEEE Trans. Autom. Control,
23(4), pp. 717–725.

[CrossRef]
Ljung,
L.
, 1979, “
Asymptotic Behavior of the Extended Kalman Filter as a Parameter Estimator for Linear Systems,” IEEE Trans. Autom. Control,
24(1), pp. 36–50.

[CrossRef]
Ursin,
B.
, 1980, “
Asymptotic Convergence Properties of the Extended Kalman Filter Using Filtered State Estimates,” IEEE Trans. Autom. Control,
25(6), pp. 1207–1211.

[CrossRef]
Reif,
K.
,
Gunther,
S.
,
Yaz,
E.
, and
Unbehauen,
R.
, 2000, “
Stochastic Stability of the Continuous-Time Extended Kalman Filter,” IEEE Proc. Control Theory Appl.,
147(1), pp. 45–72.

[CrossRef]
Reif,
K.
,
Gunther,
S.
,
Yaz,
E.
, and
Unbehauen,
R.
, 1999, “
Stochastic Stability of the Discrete-Time Extended Kalman Filter,” IEEE Trans. Autom. Control,
44(4), pp. 714–728.

[CrossRef]
Fitts,
J. M.
, 1972, “
On the Observability of Nonlinear Systems With Applications to Nonlinear Regression Analysis,” Inf. Sci.,
4(2), pp. 129–156.

[CrossRef]
Sontag,
E. D.
, 1979, “
On the Observability of Polynomial Systems—I: Finite-Time Problems,” SIAM J. Control Optim.,
17(1), pp. 139–151.

[CrossRef]
Gard,
T. C.
, 1988, Introduction to Stochastic Differential Equations,
M. Dekker, New York.

Zakai,
M.
, 1967, “
On the Ultimate Boundedness of Moments Associated With Solutions of Stochastic Differential Equations,” SIAM J. Control,
5(4), pp. 588–593.

[CrossRef]
Shanying,
Z.
,
Chen,
C.
,
Li,
W.
,
Yang,
B.
, and
Guan,
X.
, 2013, “
Distributed Optimal Consensus Filter for Target Tracking in Heterogeneous Sensor Networks,” IEEE Trans. Cybern.,
43(6), pp. 1963–1976.

[CrossRef] [PubMed]
Baras,
J. S.
,
Bensoussan,
A.
, and
James,
M. R.
, 1988, “
Dynamic Observers as Asymptotic Limits of Recursive Filters: Special Cases,” SIAM J. Appl. Math.,
48(5), pp. 1147–1158.

[CrossRef]
Gauthier,
J. P.
,
Hammouri,
H.
, and
Othman,
S.
, 1992, “
A Simple Observer for Nonlinear Systems Applications to Bioreactors,” IEEE Trans. Autom. Control,
37(6), pp. 875–880.

[CrossRef]
Khademi,
G.
,
Mohammadi,
H.
,
Hardin,
E. C.
, and
Simon,
D.
, 2015, “
Evolutionary Optimization of User Intent Recognition for Transfemoral Amputees,” IEEE Biomedical Circuits and Systems Conference (BioCAS), Atlanta, GA, Oct. 22–24, pp. 1–4.

Mao,
X.
, 2007, Stochastic Differential Equations and Applications,
Elsevier, Cambridge, UK.